@article{su_mei_mendes_tian_zhou_hu_li_2023, title={Alkalinity exacerbates phosphorus deficiency in subtropical red soils: Insights from phosphate-solubilizing fungi}, volume={5}, ISSN={["1475-2743"]}, DOI={10.1111/sum.12911}, abstractNote={Red soils in subtropical regions are often low in available phosphorus (P), a vital plant nutrient. Phosphate-solubilizing microorganisms (PSMs) can release P from phosphate reservoir, making it accessible to plants. However, the complex interactions between PSMs and minerals in red soils are not yet fully understood. In this study, we investigated the effects of Aspergillus niger, a typical phosphate-solubilizing fungus (PSF), on phosphate dissolution in two representative red soils – an acidic soil and an alkaline soil. In the acidic red soil, the fungal abundance reached 3.01 × 10 7 cfu g−1 after a 28-day incubation period, with respiration of ~2000 mg C kg−1. The secretion of oxalic acid promoted P release from inorganic phosphate (from ~1 to 187 mg kg−1). Additionally, the contents of amorphous Fe/Al oxides decreased, which otherwise could have contributed to P sorption in the soil. In contrast, P availability declined in the alkaline red soil after the addition of A. niger, regardless of the P source (inorganic or organic phosphate). Meanwhile, the fungal respiration decreased to ~780 mg C kg−1. Therefore, alkaline red soils with abundant carbonates are susceptible to P deficiency due to both the diminished function of PSMs and strong soil buffering. These findings have important implications for sustainable agriculture on alkaline red soils, as they suggest that the use of PSMs to improve P availability may be limited.}, journal={SOIL USE AND MANAGEMENT}, author={Su, Mu and Mei, Jiajie and Mendes, Gilberto de Oliveira and Tian, Da and Zhou, Limin and Hu, Shuijin and Li, Zhen}, year={2023}, month={May} }
 @article{xu_zhang_zhang_li_xia_xiao_liang_lei_he_chen_et al._2023, title={Coupled anaerobic methane oxidation and metal reduction in soil under elevated CO2}, volume={5}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.16763}, abstractNote={Continued current emissions of carbon dioxide (CO2 ) and methane (CH4 ) by human activities will increase global atmospheric CO2 and CH4 concentrations and surface temperature significantly. Fields of paddy rice, the most important form of anthropogenic wetlands, account for about 9% of anthropogenic sources of CH4 . Elevated atmospheric CO2 may enhance CH4 production in rice paddies, potentially reinforcing the increase in atmospheric CH4 . However, what is not known is whether and how elevated CO2 influences CH4 consumption under anoxic soil conditions in rice paddies, as the net emission of CH4 is a balance of methanogenesis and methanotrophy. In this study, we used a long-term free-air CO2 enrichment experiment to examine the impact of elevated CO2 on the transformation of CH4 in a paddy rice agroecosystem. We demonstrate that elevated CO2 substantially increased anaerobic oxidation of methane (AOM) coupled to manganese and/or iron oxides reduction in the calcareous paddy soil. We further show that elevated CO2 may stimulate the growth and metabolism of Candidatus Methanoperedens nitroreducens, which is actively involved in catalyzing AOM when coupled to metal reduction, mainly through enhancing the availability of soil CH4 . These findings suggest that a thorough evaluation of climate-carbon cycle feedbacks may need to consider the coupling of methane and metal cycles in natural and agricultural wetlands under future climate change scenarios.}, journal={GLOBAL CHANGE BIOLOGY}, author={Xu, Chenchao and Zhang, Naifang and Zhang, Kaihang and Li, Shuyao and Xia, Qing and Xiao, Jing and Liang, Maojun and Lei, Weilei and He, Junpan and Chen, Gaiping and et al.}, year={2023}, month={May} }
 @article{ye_wu_bai_zhou_guo_du_hu_2023, title={Interannual variation in precipitation predominantly controls mineral-associated organic carbon dynamics in a Tibetan alpine meadow}, volume={433}, ISSN={["1872-6259"]}, DOI={10.1016/j.geoderma.2023.116432}, abstractNote={Soils in alpine ecosystems store a large amount of organic carbon (C) with a significant portion sorbed to reactive soil minerals. However, impacts of ongoing global change factors on mineral-associated organic C dynamics are highly uncertain in alpine regions. Utilizing a multi-factor simulation experiment in a Tibetan alpine meadow since May 2015, we examined the effects of air warming, nitrogen input and precipitation changes on calcium (Ca)- and iron (Fe)-associated C dynamics in 2019–2020. We found no significant difference in Ca- or Fe-associated C concentrations among treatments. However, both Ca- and Fe-associated C concentrations were significantly higher in 2020 with abnormally high rainfall (+40%) than in 2019 with normal rainfall. High rainfall significantly increased soil moisture, reduced soil aggregation and released soil dissolved organic C. High soil moisture promoted the formation of both Ca- and Fe-associated C, likely through facilitating Ca-binding to clay surface as a bridge for mineral-C complexes or through increasing solubility of Fe oxides. In contrast, a low degree of water addition (<30%) immediately following each rainfall event in field did not significantly affect either Ca- or Fe-associated C. Taken together, our results provide new insights into the potential mechanisms through which interannual precipitation variability controls mineral-associated C persistence in alpine meadow ecosystems, suggesting that the pattern of rainfall change may dominate its impact on dynamics of organic C retained by reactive minerals.}, journal={GEODERMA}, author={Ye, Chenglong and Wu, Bin and Bai, Tongshuo and Zhou, Xianhui and Guo, Hui and Du, Guozhen and Hu, Shuijin}, year={2023}, month={May} }
 @article{zhang_qiu_zhao_wang_deng_chen_xu_wang_bai_he_et al._2023, title={Moderate precipitation reduction enhances nitrogen cycling and soil nitrous oxide emissions in a semi-arid grassland}, volume={3}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.16672}, abstractNote={The ongoing climate change is predicted to induce more weather extremes such as frequent drought and high-intensity precipitation events, causing more severe drying-rewetting cycles in soil. However, it remains largely unknown how these changes will affect soil nitrogen (N)-cycling microbes and the emissions of potent greenhouse gas nitrous oxide (N2O). Utilizing a field precipitation manipulation in a semi-arid grassland on the Loess Plateau, we examined how precipitation reduction (ca. −30%) influenced soil N2O and carbon dioxide (CO2) emissions in field, and in a complementary lab-incubation with simulated drying-rewetting cycles. Results obtained showed that precipitation reduction stimulated plant root turnover and N-cycling processes, enhancing soil N2O and CO2 emissions in field, particularly after each rainfall event. Also, high-resolution isotopic analyses revealed that field soil N2O emissions primarily originated from nitrification process. The incubation experiment further showed that in field soils under precipitation reduction, drying-rewetting stimulated N mineralization and ammonia-oxidizing bacteria in favor of genera Nitrosospira and Nitrosovibrio, increasing nitrification and N2O emissions. These findings suggest that moderate precipitation reduction, accompanied with changes in drying-rewetting cycles under future precipitation scenarios, may enhance N cycling processes and soil N2O emissions in semi-arid ecosystems, feeding positively back to the ongoing climate change.}, journal={GLOBAL CHANGE BIOLOGY}, author={Zhang, Kangcheng and Qiu, Yunpeng and Zhao, Yunfeng and Wang, Shuhong and Deng, Jun and Chen, Mengfei and Xu, Xinyu and Wang, Hao and Bai, Tongshuo and He, Tangqing and et al.}, year={2023}, month={Mar} }
 @article{li_yu_hao_qiu_hu_2023, title={Mycorrhizae enhance reactive minerals but reduce mineral-associated carbon}, volume={7}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.16886}, abstractNote={Abstract Soil organic carbon (C) is the largest active C pool of Earth's surface and is thus vital in sustaining terrestrial productivity and climate stability. Arbuscular mycorrhizal fungi (AMF) form symbioses with most terrestrial plants and critically modulate soil C dynamics. Yet, it remains unclear whether and how AMF–root associations (i.e., mycorrhizae) interact with soil minerals to affect soil C cycling. Here we showed that the presence of both roots and AMF increased soil dissolved organic C and reactive Fe minerals, as well as litter decomposition and soil CO 2 emissions. However, it reduced mineral‐associated C. Also, high‐resolution nanoscale secondary ion mass spectrometry images showed the existence of a thin coating (0.5–1.0 μm thick) of 56 Fe 16 O − (Fe minerals) on the surface of 12 C 14 N − (fungal biomass), illustrating the close physical association between fungal hyphae and soil Fe minerals. In addition, AMF genera were divergently related to reactive Fe minerals, with Glomus being positively but Paraglomus and Acaulospora negatively correlated with reactive Fe minerals. Moreover, the presence of roots and AMF, particularly when combined with litter addition, enhanced the abundances of several critical soil bacterial genera that are associated with the formation of reactive minerals in soils. A conceptual framework was further proposed to illustrate how AMF–root associations impact soil C cycling in the rhizosphere. Briefly, root exudates and the inoculated AMF not only stimulated the decomposition of litter and SOC and promoted the production of CO 2 emission, but also drove soil C persistence by unlocking mineral elements and promoting the formation of reactive minerals. Together, these findings provide new insights into the mechanisms that underlie the formation of reactive minerals and have significant implications for understanding and managing soil C persistence.}, journal={GLOBAL CHANGE BIOLOGY}, author={Li, Huan and Yu, Guang-Hui and Hao, Liping and Qiu, Yunpeng and Hu, Shuijin}, year={2023}, month={Jul} }
 @article{bai_wang_qiu_zhang_hu_2023, title={Nitrogen availability mediates soil carbon cycling response to climate warming: A meta-analysis}, volume={2}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.16627}, abstractNote={Global climate warming may induce a positive feedback through increasing soil carbon (C) release to the atmosphere. Although warming can affect both C input to and output from soil, direct and convincing evidence illustrating that warming induces a net change in soil C is still lacking. We synthesized the results from field warming experiments at 165 sites across the globe and found that climate warming had no significant effect on soil C stock. On average, warming significantly increased root biomass and soil respiration, but warming effects on root biomass and soil respiration strongly depended on soil nitrogen (N) availability. Under high N availability (soil C:N ratio < 15), warming had no significant effect on root biomass, but promoted the coupling between effect sizes of root biomass and soil C stock. Under relative N limitation (soil C:N ratio > 15), warming significantly enhanced root biomass. However, the enhancement of root biomass did not induce a corresponding C accumulation in soil, possibly because warming promoted microbial CO2 release that offset the increased root C input. Also, reactive N input alleviated warming-induced C loss from soil, but elevated atmospheric CO2 or precipitation increase/reduction did not. Together, our findings indicate that the relative availability of soil C to N (i.e., soil C:N ratio) critically mediates warming effects on soil C dynamics, suggesting that its incorporation into C-climate models may improve the prediction of soil C cycling under future global warming scenarios.}, journal={GLOBAL CHANGE BIOLOGY}, author={Bai, Tongshuo and Wang, Peng and Qiu, Yunpeng and Zhang, Yi and Hu, Shuijin}, year={2023}, month={Feb} }
 @article{wang_huang_song_yuan_li_zhu_chang_luo_ciais_penuelas_et al._2023, title={Reduced phosphorus availability in paddy soils under atmospheric CO2 enrichment}, volume={1}, ISSN={["1752-0908"]}, DOI={10.1038/s41561-022-01105-y}, journal={NATURE GEOSCIENCE}, author={Wang, Yu and Huang, Yuanyuan and Song, Lian and Yuan, Jiahui and Li, Wei and Zhu, Yongguan and Chang, Scott X. and Luo, Yiqi and Ciais, Philippe and Penuelas, Josep and et al.}, year={2023}, month={Jan} }
 @misc{liu_sayer_deng_li_liu_wang_yang_huang_luo_su_et al._2023, title={The grassland carbon cycle: Mechanisms, responses to global changes, and potential contribution to carbon neutrality}, volume={3}, ISSN={["2667-3258"]}, DOI={10.1016/j.fmre.2022.09.028}, abstractNote={Grassland is one of the largest terrestrial biomes, providing critical ecosystem services such as food production, biodiversity conservation, and climate change mitigation. Global climate change and land-use intensification have been causing grassland degradation and desertification worldwide. As one of the primary medium for ecosystem energy flow and biogeochemical cycling, grassland carbon (C) cycling is the most fundamental process for maintaining ecosystem services. In this review, we first summarize recent advances in our understanding of the mechanisms underpinning spatial and temporal patterns of the grassland C cycle, discuss the importance of grasslands in regulating inter- and intra-annual variations in global C fluxes, and explore the previously unappreciated complexity in abiotic processes controlling the grassland C balance, including soil inorganic C accumulation, photochemical and thermal degradation, and wind erosion. We also discuss how climate and land-use changes could alter the grassland C balance by modifying the water budget, nutrient cycling and additional plant and soil processes. Further, we examine why and how increasing aridity and improper land use may induce significant losses in grassland C stocks. Finally, we identify several priorities for future grassland C research, including improving understanding of abiotic processes in the grassland C cycle, strengthening monitoring of grassland C dynamics by integrating ground inventory, flux monitoring, and modern remote sensing techniques, and selecting appropriate plant species combinations with suitable traits and strong resistance to climate fluctuations, which would help design sustainable grassland restoration strategies in a changing climate.}, number={2}, journal={FUNDAMENTAL RESEARCH}, author={Liu, Lingli and Sayer, Emma J. and Deng, Meifeng and Li, Ping and Liu, Weixing and Wang, Xin and Yang, Sen and Huang, Junsheng and Luo, Jie and Su, Yanjun and et al.}, year={2023}, month={Mar}, pages={209–218} }
 @article{deng_hu_guo_jiang_huang_schmid_liu_chang_li_liu_et al._2023, title={Tree mycorrhizal association types control biodiversity- relationship in a subtropical forest}, volume={9}, ISSN={["2375-2548"]}, DOI={10.1126/sciadv.add4468}, abstractNote={Mycorrhizae are symbiotic associations between terrestrial plants and fungi in which fungi obtain nutrients in exchange for plant photosynthates. However, it remains unclear how different types of mycorrhizae affect their host interactions and productivity. Using a long-term experiment with a diversity gradient of arbuscular (AM) and ectomycorrhizal (EcM) tree species, we show that the type of mycorrhizae critically controls the effect of diversity on productivity. With increasing diversity, the net primary production of AM trees increased, but EcM trees decreased, largely because AM trees are more effective in acquiring nitrogen and phosphorus. Specifically, with diversity increase, AM trees enhance both nutrient resorption and litter decomposition, while there was a trade-off between litter decomposability and nutrient resorption in EcM trees. These results provide a mechanistic understanding of why AM trees using a different nutrient acquisition strategy from EcM trees can dominate in subtropical forests and at the same time their diversity enhances productivity.}, number={3}, journal={SCIENCE ADVANCES}, author={Deng, Meifeng and Hu, Shuijin and Guo, Lulu and Jiang, Lin and Huang, Yuanyuan and Schmid, Bernhard and Liu, Chao and Chang, Pengfei and Li, Shan and Liu, Xiaojuan and et al.}, year={2023}, month={Jan} }
 @article{zhang_qiu_gilliam_gillespie_tu_reberg-horton_hu_2022, title={Arbuscular Mycorrhizae Shift Community Composition of N-Cycling Microbes and Suppress Soil N2O Emission}, volume={8}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.2c03816}, abstractNote={Mycorrhizae are ubiquitous symbiotic associations between arbuscular mycorrhizal fungi (AMF) and terrestrial plants, in which AMF receive photosynthates from and acquire soil nutrients for their host plants. Plant uptake of soil nitrogen (N) reduces N substrate for microbial processes that generate nitrous oxide (N2O), a potent greenhouse gas. However, the underlying microbial mechanisms remain poorly understood, particularly in agroecosystems with high reactive N inputs. We examined how plant roots and AMF affect N2O emissions, N2O-producing (nirK and nirS) and N2O-consuming (nosZ) microbes under normal and high N inputs in conventional (CONV) and organically managed (OM) soils. Here, we show that high N input increased soil N2O emissions and the ratio of nirK to nirS microbes. Roots and AMF did not affect the (nirK + nirS)/nosZ ratio but significantly reduced N2O emissions and the nirK/nirS ratio. They reduced the nirK/nirS ratio by reducing nirK-Rhodobacterales but increasing nirS-Rhodocyclales in the CONV soil while decreasing nirK-Burkholderiales but increasing nirS-Rhizobiales in the OM soil. Our results indicate that plant roots and AMF reduced N2O emission directly by reducing soil N and indirectly through shifting the community composition of N2O-producing microbes in N-enriched agroecosystems, suggesting that harnessing the rhizosphere microbiome through agricultural management might offer additional potential for N2O emission mitigation.}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Zhang, Xuelin and Qiu, Yunpeng and Gilliam, Frank S. and Gillespie, Christopher J. and Tu, Cong and Reberg-Horton, S. Chris and Hu, Shuijin}, year={2022}, month={Aug} }
 @article{ye_huang_hall_hu_2022, title={Association of Organic Carbon With Reactive Iron Oxides Driven by Soil pH at the Global Scale}, volume={36}, ISSN={["1944-9224"]}, DOI={10.1029/2021GB007128}, number={1}, journal={GLOBAL BIOGEOCHEMICAL CYCLES}, author={Ye, Chenglong and Huang, Wenjuan and Hall, Steven J. and Hu, Shuijin}, year={2022}, month={Jan} }
 @article{hu_sai_guo_guo_zhou_hu_wang_2022, title={Effects of an actinorhizal shrub on the nitrogen status of the soil and neighboring plants in an alpine meadow of the Tibetan Plateau}, volume={8}, ISSN={["1664-221X"]}, DOI={10.1007/s00035-022-00287-w}, journal={ALPINE BOTANY}, author={Hu, Lingyan and Sai, Jiuma and Guo, Jin and Guo, Hui and Zhou, Xianhui and Hu, Shuijin and Wang, Peng}, year={2022}, month={Aug} }
 @article{wang_mou_hu_hu_2022, title={Effects of nutrient heterogeneity on root foraging and plant growth at the individual and community level}, volume={9}, ISSN={["1460-2431"]}, DOI={10.1093/jxb/erac358}, abstractNote={Abstract Plants enhance nutrient uptake in heterogeneous nutrient environments through selective root placement. Many studies have documented that plants grow better under heterogeneous than under homogeneous nutrient distribution, but comprehensive syntheses are relatively few. In a meta-analysis, we examined the effects of patch scale and contrast on plant responses by synthesizing the effects of nutrient heterogeneity on root foraging and plant growth in 131 comparative studies. Plant responses to nutrient heterogeneity were phylogenetically conserved, and the response in shoot biomass was significantly correlated with the response in root biomass but not with root foraging precision. Root precision depended on the competition regime, and plants had lower precision in interspecific than in conspecific competition. Community-level growth was significantly promoted by nutrient heterogeneity and was less variable than individual-level responses. Along with increasing patch scale, overall shoot and root responses of individuals increased but root foraging precision declined. In addition, moderate patch contrast induced the highest root responses. Our results indicate that plants optimize nutrient acquisition from heterogeneous patches mainly through increasing root growth, and plant communities exploit heterogeneous nutrients more effectively than individuals. Understanding the roles of patch attributes in nutrient-heterogeneity effects may help in designing fertilization practices to promote productivity and conserve biodiversity.}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={Wang, Peng and Mou, Pu and Hu, Lingyan and Hu, Shuijin}, year={2022}, month={Sep} }
 @article{zhang_zhang_hu_2022, title={Fungivorous nematode Aphelenchus avenae and collembola Hypogastrura perplexa alleviate damping-off disease caused by Pythium ultimum in tomato}, volume={9}, ISSN={["1573-5036"]}, DOI={10.1007/s11104-022-05680-2}, journal={PLANT AND SOIL}, author={Zhang, Pei and Zhang, Weijian and Hu, Shuijin}, year={2022}, month={Sep} }
 @article{bloszies_reberg-horton_heitman_woodley_grossman_hu_2022, title={Legume cover crop type and termination method effects on labile soil carbon and nitrogen and aggregation}, volume={4}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.21022}, DOI={10.1002/agj2.21022}, abstractNote={Growers use cover crops to provide nutrients for crops and build soil organic matter. Termination methods may alter the effects of cover crops on soil labile C and N. We examined how two cover crops and three termination methods affected soil microbes, soil aggregates, and C and N pools in an organic grain system. We compared crimson clover (Trifolium incarnatum L.), hairy vetch (Vicia villosa Roth), and a control together with disking, mowing, or a roller-crimper for effects on hot-water-extractable carbohydrates, microbial biomass C (MBC) and N, potentially mineralizable C and N, and aggregation (quantified by mean weight diameter, MWD). Disking comprised flail mowing plots and then cultivating. Roller-crimping occurred via a roller with blades. Vetch soil contained 14% higher MBC than no cover crop pre-termination, possibly because of enhanced rhizodeposition. Planting crimson clover resulted in 44% higher MBC than no cover crop a week after termination, likely due to its higher biomass C:N ratio. Disking decreased MWD relative to flail mowing in no cover crop soils at four weeks after termination across both years at 0–5 cm depth. In addition, MWD was lower under crimson clover than under no cover crop for both the flail mowed and roller-crimped treatments at four weeks after termination across both years from 0–5 cm. This is possibly due to enhanced desiccation of the soil in bare plots after termination. Our results indicate that quantity and quality of biomass of different legume species, rather than termination methods, dominated impacts on labile C. Disking lowered aggregation in non-planted plots versus flail-mowing Hairy vetch raised mineralizable N versus crimson clover or no cover crop, even before termination Mowing cover crops did not increase soil microbial activity compared to rolling This article is protected by copyright. All rights reserved}, number={3}, journal={AGRONOMY JOURNAL}, publisher={Wiley}, author={Bloszies, Sean A. and Reberg-Horton, S. Chris and Heitman, Joshua L. and Woodley, Alex L. and Grossman, Julie M. and Hu, Shuijin}, year={2022}, month={Apr} }
 @article{wu_chen_delgado-baquerizo_liu_wang_wu_hu_bai_2022, title={Long-term regional evidence of the effects of livestock grazing on soil microbial community structure and functions in surface and deep soil layers}, volume={168}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2022.108629}, abstractNote={Grazing by livestock can affect plant biodiversity and topsoil functions. However, experimental evidence on whether these impacts are limited to the topsoil or penetrate into deep layers (via changes in soil environment and resource locations) of soil is lacking, especially for soil microbial biomass and diversity. Here, we used paired grazed and ungrazed (fenced) plots at 10 locations across the Mongolian Plateau to investigate how long-term (>10 years) livestock grazing affects the biomass, diversity, composition, and function of microbial communities in surface (0–20 cm) and deep soil layers (40–60 cm). Livestock grazing increased bacterial diversity by 5–9% in both soil layers but increased fungal diversity by 10% only in the topsoil. Livestock grazing also strongly altered bacterial and fungal community composition in both soil layers. Livestock grazing decreased soil C mineralization rates by 11–25% in both soil layers, and decreased soil N mineralization rates by 16% and bacterial biomass by 20% only in the topsoil. The grazing-induced increase in microbial diversity in both soil layers was mainly explained by the changes in plant C:N ratio and plant biomass rather than by soil abiotic variables, especially for the deep soil layer. The grazing-induced negative effects on ecosystem functions (soil C and N mineralization) were mainly associated with soil abiotic variables together with plant variables or microbial diversity in the surface soil layer and were mainly associated with plant variables and soil microbial diversity in the deep soil layer. Overall, our regional field experiment provides the first evidence that the strong effects of livestock grazing on soil microbial biomass, diversity, composition, and function can penetrate the deep soil in arid and semi-arid grasslands. This knowledge suggests that models should consider the dynamic interactions between land use and both soil microbial diversity and biomass across soil depths in global drylands. Conceptual diagram showing the effects of livestock grazing on the soil microbial community structure and functions in surface and deep soil layers on the Mongolia Plateau. We investigated how large herbivore grazing affects biomass and diversities of soil bacterial and fungal communities and ecosystem functions in both surface and deep soil layers using paired grazed and ungrazed plots at 10 locations across the Mongolian Plateau. Our results provide the first evidence that the strong effects of livestock grazing on soil microbial biomass, diversity, composition, and function can penetrate to a deep soil layer on arid and semi-arid grasslands. The findings suggest that models should consider the dynamic interactions between land use and both soil microbial biomass and diversity across soil depths in global drylands. • Livestock grazing increased soil bacterial diversity in both topsoil and deep soils. • Livestock grazing increased soil fungal diversity only in the topsoil. • Livestock grazing decreased soil bacterial biomass only in the topsoil. • Grazing effects on soil bacteria were stronger than on soil fungi across soil depths. • Grazing effects on soil microbes and functions can penetrate the deeper soils.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Wu, Ying and Chen, Dima and Delgado-Baquerizo, Manuel and Liu, Shengen and Wang, Bing and Wu, Jianping and Hu, Shuijin and Bai, Yongfei}, year={2022}, month={May} }
 @article{yan_kohli_wen_wang_zhang_yang_zhou_du_hu_guo_2022, title={Nitrogen addition and warming modulate the pathogen impact on plant biomass by shifting intraspecific functional traits and reducing species richness}, volume={12}, ISSN={["1365-2745"]}, DOI={10.1111/1365-2745.14043}, abstractNote={Abstract Foliar fungal pathogens can substantially reduce plant biomass. This effect can be modulated by environment conditions, such as soil nitrogen availability and air temperature. The ongoing global changes are altering these variables and thus interact with pathogens to influence plant biomass, but experimental test of their interactions is scarce. We conducted a 4‐year field experiment in a Tibetan alpine meadow to examine the interactive effects of nitrogen addition, warming and foliar pathogens (via fungicide application) on plant biomass. We also measured plant functional traits, species richness and abundance to test the possible mechanisms underlying these interactions. Our results showed that foliar fungal pathogens reduced plant community biomass under nitrogen addition, which in turn weakened the positive nitrogen effect on community biomass. Mechanistically, nitrogen addition shifted the plant communities towards fast‐growing traits; this happened predominantly because of changes in within‐species trait values, including an increase in specific leaf area and height. These trait changes resulted in greater suppression of plant biomass by pathogens, likely because of the trade‐offs associated with the allocation of resources to plant growth and defense. Moreover, the reduction in species richness amplified the pathogen effect under nitrogen addition due to the increased density and susceptibility of the most dominant species (i.e. Kobresia capillifolia ). Furthermore, warming did not interact with pathogens and nitrogen addition to influence plant community biomass, but their three‐way interaction modified the biomass of K. capillifolia . Specifically, warming enhanced the positive effect of nitrogen addition on the biomass of K. capillifolia in the fungicide, low infection plots, while it weakened the nitrogen effect in the no fungicide, high infection plots. Synthesis . Our results demonstrate how pathogens interact with nitrogen addition and warming to influence the biomass of dominant species and the whole plant community. Our study highlights the importance of considering foliar fungal pathogens when assessing ecosystem responses to multiple global change factors.}, journal={JOURNAL OF ECOLOGY}, author={Yan, Xuebin and Kohli, Mayank and Wen, Yue and Wang, Xiaoyi and Zhang, Yuanyuan and Yang, Fei and Zhou, Xianhui and Du, Guozhen and Hu, Shuijin and Guo, Hui}, year={2022}, month={Dec} }
 @article{xie_ren_chen_yang_zheng_chen_wang_li_hu_xu_2022, title={Plant nitrogen nutrition: The roles of arbuscular mycorrhizal fungi}, volume={269}, ISSN={["1618-1328"]}, DOI={10.1016/j.jplph.2021.153591}, abstractNote={Nitrogen (N) is the most abundant mineral nutrient required by plants, and crop productivity depends heavily on N fertilization in many soils. Production and application of N fertilizers consume huge amounts of energy and substantially increase the costs of agricultural production. Excess N compounds released from agricultural systems are also detrimental to the environment. Thus, increasing plant N uptake efficiency is essential for the development of sustainable agriculture. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most terrestrial plants that facilitate plant nutrient uptake and increase host resistance to diverse environmental stresses. AM association is an endosymbiotic process that relies on the differentiation of both host plant roots and AM fungi to create novel contact interfaces within the cells of plant roots. AM plants have two pathways for nutrient uptake: either direct uptake via the root hairs and root epidermis, or indirectly through AM fungal hyphae into root cortical cells. Over the last few years, great progress has been made in deciphering the molecular mechanisms underlying the AM-mediated modulation of nutrient uptake processes, and a growing number of fungal and plant genes responsible for the uptake of nutrients from soil or transfer across the fungi-root interface have been identified. Here, we mainly summarize the recent advances in N uptake, assimilation, and translocation in AM symbiosis, and also discuss how N interplays with C and P in modulating AM development, as well as the synergies between AM fungi and soil microbial communities in N uptake.}, journal={JOURNAL OF PLANT PHYSIOLOGY}, author={Xie, Kun and Ren, Yuhan and Chen, Aiqun and Yang, Congfan and Zheng, Qingsong and Chen, Jun and Wang, Dongsheng and Li, Yiting and Hu, Shuijin and Xu, Guohua}, year={2022}, month={Feb} }
 @article{cheng_li_zhang_lu_chen_yao_dong_ma_yuan_xu_et al._2021, title={Autopolyploidy-driven range expansion of a temperate-originated plant to pan-tropic under global change}, volume={91}, ISSN={["1557-7015"]}, DOI={10.1002/ecm.1445}, abstractNote={Angiosperms are believed to have emerged initially in the tropics and expanded their distribution range poleward through diverse mechanisms, for example polyploidization-driven cold tolerance evolution. Reversed expansion from temperate to pan-tropic climates through a polyploidization-driven shift in heat tolerance remains largely unknown. Here, we found autopolyploidy in relation to the global expansion of Solidago canadensis from its temperate-climate native range in North American to hot-summer climate in an introduced range. Our cytogeographical study of 2,062 accessions from 471 locations worldwide demonstrates that ploidy levels correlate negatively with latitude and positively with average temperature. An isotherm-dependent shift of the climate niches at the threshold of 20°–24°C between geo-cytotypes can be attributed mainly to autopolyploidy-driven differentiation of heat tolerance; only polyploids and not diploids are able to complete sexual reproduction, germinate, and grow in the hot-summer climate of low latitudes. Ploidy-dependent fertility appears to play a key role in the hot-summer introduced range in the northern hemisphere through both pre-adaptation and rapid post-introduction adaptive evolution of delayed flowering and improved heat tolerance during embryo development. The MaxEnt model predicts continued expansion of this plant species under global change. These results provide new insights into the mechanisms governing autopolyploidy-driven backward range expansion of plant species from temperate origins.}, number={2}, journal={ECOLOGICAL MONOGRAPHS}, author={Cheng, Jiliang and Li, Jun and Zhang, Zheng and Lu, Huan and Chen, Guoqi and Yao, Beibei and Dong, Yingxue and Ma, Ling and Yuan, Xiaoxiao and Xu, Jingxuan and et al.}, year={2021}, month={May} }
 @article{li_wang_su_wang_li_bai_wei_liu_chen_zhu_et al._2021, title={Climate change drivers alter root controls over litter decomposition in a semi-arid grassland}, volume={158}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2021.108278}, abstractNote={Plant roots are the primary source of soil organic carbon (C) and critically support the growth and activities of microbes in the rhizosphere. Climate change factors may, however, modify root-microbial interactions and impact C dynamics in the rhizosphere. Yet, the direction and magnitude of interactive climate change effects, as well as the underlying mechanisms, remain unclear. Here we show evidence from a field experiment demonstrating that warming and precipitation changes strengthen root controls over litter decomposition in a semi-arid grassland. While warming and precipitation reduction suppressed microbial decomposition of root litter regardless of the root presence, precipitation increase stimulated litter decomposition only in the absence of roots, suggesting that plant competition for water constraints the activities of saprophytic microbes. Root presence increased microbial biomass but reduced microbial activities such as respiration, C cycling enzymes and litter decomposition, indicating that roots exert differential effects on microbes through altering C or water availability. In addition, nitrogen (N) input significantly reduced microbial biomass and microbial activities (respiration). Together, these results showed that alterations in soil moisture induced by climate change drivers critically modulate root controls over microbial decomposition in soil. Our findings suggest that warming-enhanced plant water utilization, combined with N-induced suppression of microbes, may provide a unique mechanism through which moderate increases in precipitation, warming and N input interactively suppress microbial decomposition, thereby facilitating short-term soil C sequestration in the arid and semi-arid grasslands.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Li, Zhen and Wang, Fuwei and Su, Fanglong and Wang, Peng and Li, Shijie and Bai, Tongshuo and Wei, Yanan and Liu, Manqiang and Chen, Dima and Zhu, Weixing and et al.}, year={2021}, month={Jul} }
 @article{xu_qiu_zhang_yang_chen_luo_yan_wang_zhang_chen_et al._2021, title={Climate warming promotes deterministic assembly of arbuscular mycorrhizal fungal communities}, volume={11}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.15945}, abstractNote={Arbuscular mycorrhizal fungi (AMF) significantly contribute to plant resource acquisition and play important roles in mediating plant interactions and soil carbon (C) dynamics. However, it remains unclear how AMF communities respond to climate change. We assessed impacts of warming and precipitation alterations (30% increase or decrease) on soil AMF communities, and examined major ecological processes shaping the AMF community assemblage in a Tibetan alpine meadow. Our results showed that warming significantly increased root biomass, and available nitrogen (N) and phosphorus (P) in soil. While precipitation alterations increased AMF abundances, they did not significantly affect the composition or diversity of AMF communities. In contrast, warming altered the composition of AMF communities and reduced their Shannon-Wiener index and Pielou's evenness. In particular, warming shifted the AMF community composition in favor of Diversisporaceae over Glomeraceae, likely through its impact on soil N and P availability. In addition, AMF communities were phylogenetically random in the unwarmed control but clustered in warming plots, implying more deterministic community assembly under climate warming. Warming enhancement of root growth, N and P availability likely reduced plant C-allocation to AMF, imposing stronger environmental filtering on AMF communities. We further proposed a conceptual framework that integrates biological and geochemical processes into a mechanistic understanding of warming and precipitation changes' effects on AMF. Taken together, these results suggest that soil AMF communities may be more sensitive to warming than expected, highlighting the need to monitor their community structure and associated functional consequences on plant communities and soil C dynamics under the future warmer climate.}, journal={GLOBAL CHANGE BIOLOGY}, author={Xu, Xinyu and Qiu, Yunpeng and Zhang, Kangcheng and Yang, Fei and Chen, Mengfei and Luo, Xi and Yan, Xuebin and Wang, Peng and Zhang, Yi and Chen, Huaihai and et al.}, year={2021}, month={Nov} }
 @article{li_zhang_sun_hu_wang_hu_li_xu_jiao_2021, title={Combination of plant-growth-promoting and fluoranthene-degrading microbes enhances phytoremediation efficiency in the ryegrass rhizosphere}, volume={28}, ISSN={["1614-7499"]}, DOI={10.1007/s11356-020-10937-3}, number={5}, journal={ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH}, author={Li, Weiming and Zhang, Zhen and Sun, Bin and Hu, Shuijin and Wang, Dongsheng and Hu, Feng and Li, Huixin and Xu, Li and Jiao, Jiaguo}, year={2021}, month={Feb}, pages={6068–6077} }
 @article{bai_wang_ye_hu_2021, title={Form of nitrogen input dominates N effects on root growth and soil aggregation: A meta-analysis}, volume={157}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2021.108251}, abstractNote={Anthropogenic nitrogen (N) input has overtaken natural N fixation as the largest reactive N source and is predicted to stimulate ecosystem carbon (C) sequestration. Most studies of N effects on soil C balance have focused on biological processes that control C input (plant production) and C output (microbial decomposition), but few have examined the general patterns of N effects on the physiochemical processes that regulate soil organic C persistence. We synthesized results from 87 publications that examined effects of experimental N input on soil aggregation, a key process controlling soil C persistence, and its related processes. Globally, N input significantly enhanced plant shoot and root biomass, and the formation of soil macroaggregates and their size (measured as mean weight diameter, MWD; P < 0.05). Surprisingly, N-enhancement of root biomass and soil aggregation primarily stemmed from urea applications. Although urea input reduced microaggregates, it increased macroaggregates (+6.9%) and MWD, likely due to enmeshment by urea-induced root growth (+20.5%). In contrast, other forms of N input (combined NH4+, NO3− and NH4NO3) did not significantly affect root biomass, microaggregates or macroaggregates, but reduced microbial biomass C. Further, N-promotion of soil aggregation occurred mainly in croplands under low to moderate N input (<200 kg N ha−1 yr−1). Together, these results indicate that the form of N fertilizer exerts a primary control over N effects on plants, microbes, and soil aggregation. Our findings suggest that combination of urea fertilizers and reduced perturbations (e.g., reduced-tillage) may be key to enhance soil aggregation and organic C retention and persistence in vast agroecosystems.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Bai, Tongshuo and Wang, Peng and Ye, Chenglong and Hu, Shuijin}, year={2021}, month={Jun} }
 @article{wang_wu_chen_hu_bai_2021, title={Legacy effect of grazing intensity mediates the bottom-up controls of resource addition on soil food webs}, volume={58}, ISSN={["1365-2664"]}, DOI={10.1111/1365-2664.13825}, abstractNote={Abstract Large‐scale studies have demonstrated that nitrogen (N) and water (W) availabilities greatly affect terrestrial ecosystems world‐wide, and this is especially true for the resource‐poor semi‐arid grasslands. Yet, experimental evidence is lacking for how N and W availabilities affect soil food webs across historical grazing intensity‐altered environments at a local scale. Here, we included N‐ and W‐addition treatments in an 8‐year grazing experiment (with four grazing intensities) to determine how the legacy effects of grazing intensity mediate the responses of key components of soil food webs (plants, micro‐organisms and nematodes) to resource addition in a semi‐arid grassland. After 4 years of N‐ and W‐addition treatments (with no grazing during that 4‐year period), we found that a legacy of grazing, even light grazing, had significant negative effects on the components of plant community and soil food webs. Both N and W addition increased above‐ and below‐ground plant biomass, especially under moderate and heavy grazing. N addition had negative effects on the biomass of bacteria under no grazing, while W addition increased the biomass of actinomycetes under light grazing. N addition decreased the abundance of omnivorous + carnivorous nematodes under light and heavy grazing, while W addition increased their abundance under heavy grazing. Overall, the effects of resource addition on soil food webs progressively decreased from the lowest trophic level (primary producers, i.e. plants), to intermediate trophic levels (micro‐organisms and root‐feeding nematodes), to higher trophic levels (microbial‐feeding nematodes and omnivorous + carnivorous nematodes). Synthesis and applications . Our results, which are the first data concerning the effects of resource addition on key components of soil food webs across a historical grazing‐induced environmental gradient, show that the strong bottom‐up controls of resource addition on soil food webs are mediated by the legacy of grazing intensity. These findings should be useful for predicting the responses of grassland ecosystems to future climate change and suggest that the recovery of degraded grasslands will require more than restoration measure of resource inputs alone.}, number={5}, journal={JOURNAL OF APPLIED ECOLOGY}, author={Wang, Bing and Wu, Ying and Chen, Dima and Hu, Shuijin and Bai, Yongfei}, year={2021}, month={May}, pages={976–987} }
 @article{liu_bei_wang_liu_hu_lin_zhang_lin_jin_hu_et al._2021, title={Microbial metabolic efficiency and community stability in high and low fertility soils following wheat residue addition}, volume={159}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2020.103848}, abstractNote={Soil microbial metabolic efficiency and microbial community stability following the amendment of plant residue to soils are of great importance to the improvement of soil carbon storage and soil fertility. However, heterogeneity of microbial metabolic efficiency and community stability in soils with different fertility defined based on the crop yield, as well as the underlying mechanisms still remains elusive. Here, soils with high and low fertility (HF and LF) were incubated with 13C-labeled wheat residue and analyzed periodically for microbial metabolic quotient and functional bacterial populations using DNA-stable isotope probing technique combined with high-throughput sequencing. Results revealed that soil organic matter (SOM) decomposers following wheat residue amendment were suppressed in HF but stimulated in LF, leading to a higher microbial metabolic efficiency and lower priming effect in HF. This difference in SOM decomposers' responses could be due to that microbes in nutrient- limited LF has to mine recalcitrant SOM for nutrient requirement to support the utilization of wheat residue, the ample nutrients in HF, however, render the microbes to directly utilize wheat residue. Both the resistance (disturbance stability) and resilience (temporal stability) of bacterial community were higher in HF than in LF following disturbance of wheat residue addition. Higher abundance and lower composition variation of wheat residue decomposers in HF than in LF might result in the higher stability of microbial community in HF. The results suggest that plant residue amendment to fertile soils is likely more effective for soil carbon accumulation and soil fertility buildup than to infertile soils, due to higher microbial metabolic efficiency and higher microbial community stability.}, journal={APPLIED SOIL ECOLOGY}, author={Liu, Benjuan and Bei, Qicheng and Wang, Xiaojie and Liu, Qi and Hu, Shuijin and Lin, Zhibin and Zhang, Yanhui and Lin, Xingwu and Jin, Haiyang and Hu, Tianlong and et al.}, year={2021}, month={Mar} }
 @article{yang_zhang_barberan_yang_hu_guo_2021, title={Nitrogen-induced acidification plays a vital role driving ecosystem functions: Insights from a 6-year nitrogen enrichment experiment in a Tibetan alpine meadow}, volume={153}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2020.108107}, abstractNote={Anthropogenic nitrogen (N) input has overtaken natural N fixation as the leading source of reactive N, and can profoundly alter the structure and functions of terrestrial ecosystems. N input impacts ecosystem functions through altering abiotic (e.g., soil nutrients and pH) and biotic (e.g., biological community composition) properties, but the relative importance of these abiotic and biotic effects remains largely unknown. We conducted a 6-year experiment of N manipulations (0, 5, 10, and 20 g N m−2 yr−1) in a Tibetan alpine meadow to assess N-induced abiotic and biotic effects on ecosystem functions. A complementary experiment with acid additions (0, 0.66, 2.65, 4.63, and 7.28 mol H+ m−2 yr−1) was also carried out to examine the direct impact of acidification. We found that N enrichment significantly increased plant productivity but decreased soil microbial respiration. While the increased productivity was associated with increased N availability, the reduction in soil microbial respiration was mainly explained by the decreased soil pH. In the acid addition experiment, enhanced soil acidity due to the increased proton concentration significantly reduced soil microbial respiration. These results indicate that N-induced changes in soil pH represent an important mechanism driving the ecosystem functions, suggesting that N-induced acidification should receive more attention for understanding and predicting ecosystem services under future N-enrichment scenarios.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Yang, Fei and Zhang, Zhilong and Barberan, Albert and Yang, Yi and Hu, Shuijin and Guo, Hui}, year={2021}, month={Feb} }
 @article{zhang_cai_hu_chang_2021, title={Plant mixture effects on carbon-degrading enzymes promote soil organic carbon accumulation}, volume={163}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2021.108457}, abstractNote={Microbial decomposition of soil organic carbon (SOC) is a major determinant of the global climate and terrestrial ecosystem services. Despite the rapid loss of plant species worldwide, it remains unclear how plant species richness impacts SOC decomposition, especially the decomposition of labile vs. recalcitrant SOC. This is partly because of the variable responses of soil C-degrading enzyme activities to plant species richness. Through a global meta-analysis of 490 paired observations of plant mixtures versus monocultures, we show that plant mixtures significantly enhanced soil C-hydrolase (degrades labile C) and C-oxidase (degrades recalcitrant C) activities by 29.4 and 14.9%, respectively. However, in mixtures, C-hydrolase activity marginally (P = 0.051) increased, while C-oxidase activity significantly decreased with plant species richness. In addition, in mixtures, C-hydrolase but not C-oxidase activity significantly increased with plant functional type richness and experimental duration. These plant species richness and functional type effects on C-hydrolase and C-oxidase activities were consistent among diverse terrestrial ecosystems, plant life forms, the presence/absence of legumes, and climate types. Moreover, increases in C-hydrolase but not C-oxidase activity were positively related with increasing microbial biomass C and SOC under plant mixtures, suggesting that faster microbial decomposition and transformation of labile C pools mediate SOC accumulation at higher plant species richness. These results highlight that plant species richness differentially affects labile and recalcitrant C-degrading enzymes, thereby influencing SOC decomposition, dynamics, and accumulation.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Zhang, Baogang and Cai, Yanjiang and Hu, Shuijin and Chang, Scott X.}, year={2021}, month={Dec} }
 @article{wang_li_wei_su_guo_guo_wang_zhang_hu_2021, title={Responses of soil ammonia-oxidizing bacteria and archaea to short-term warming and nitrogen input in a semi-arid grassland on the Loess Plateau}, volume={102}, ISSN={["1778-3615"]}, DOI={10.1016/j.ejsobi.2020.103267}, abstractNote={Ammonia-oxidizing archaea (AOA) and bacteria (AOB) predominantly control ammonia oxidation, the first and rate-limiting step of nitrification, and critically affect plant utilization and the fate of reactive nitrogen (N) input to soil. Both AOA and AOB are often sensitive to environmental changes, but their responses to the concurrent climate warming and N input remain poorly understood, particularly in semi-arid grassland ecosystems where nitrification dominates soil N transformations. We examined the interactive effects of short-term (2-yr) warming and N input (12 g N m−2 y−1) on the abundance and community structure of AOA and AOB in a semi-arid grassland on China's Loess Plateau. Results showed that AOA abundance was significantly higher than AOB in all treatments. N input significantly increased the abundance of AOA and AOB by 32% and 521%, respectively, and induced a significant shift in the AOB community composition. Warming significantly increased the abundance of AOB by 94%, but had no impact on the AOA abundance. Warming (alone or combined with N input) did not significantly affect the community structure of AOA or AOB. These results indicated that AOB was more sensitive to N input and climate warming than AOA in semi-arid Loess grasslands. Our findings suggest that understanding the responses of AOB abundance and composition may be key to predict the N dynamics under future global change scenarios.}, journal={EUROPEAN JOURNAL OF SOIL BIOLOGY}, author={Wang, Fuwei and Li, Zhen and Wei, Yanan and Su, Fanglong and Guo, Hui and Guo, Jiuxin and Wang, Yi and Zhang, Yi and Hu, Shuijin}, year={2021} }
 @article{wang_li_su_guo_wang_guo_zhu_wang_hu_2021, title={Sensitive Groups of Bacteria Dictate Microbial Functional Responses to Short-term Warming and N Input in a Semiarid Grassland}, volume={10}, ISSN={["1435-0629"]}, DOI={10.1007/s10021-021-00719-4}, journal={ECOSYSTEMS}, author={Wang, Fuwei and Li, Zhen and Su, Fanglong and Guo, Hui and Wang, Peng and Guo, Jiuxin and Zhu, Weixing and Wang, Yi and Hu, Shuijin}, year={2021}, month={Oct} }
 @article{ren_cai_rodrigues_wu_wang_chang_wu_zhou_jiang_hu_2021, title={Species patch size at seeding affects the productivity of mixed legume-grass communities}, volume={129}, ISSN={["1873-7331"]}, DOI={10.1016/j.eja.2021.126342}, abstractNote={The impact of inter- and intraspecific neighboring plants on mixed legume-grass communities has rarely been explored in relation to seeded species patch size. In this study, two native perennial species, the legume alfalfa (Medicago sativa L.) and the grass tall fescue (Festuca arundinacea L.), were investigated as monocultures and in mixture. A three-year growth experiment was conducted to investigate the effects of plant-plant competitive interactions on fine-scale seeding patterns: monoculture, three different conspecific patch sizes (1.0, 0.5, and 0.25 m side length of squares) and a control in which the seeds were mixed and scattered (i.e., patches were not formed) as in conventional seeding. The results demonstrated significant differences in the mutual effect intensity in all conspecific patch sizes, indicating the presence of grass-legume interactions on mixed plant communities. Smaller patch sizes resulted in better facilitation by higher neighbor effect intensity when compared with a larger patch size and the conventional mixture. Seedings in the smallest patch size of 0.25 m × 0.25 m showed intra- and interspecific competition and significantly improved aboveground productivity compared with the other patch sizes. We directly quantified the variation of species neighbor effect intensity between grass and legume mixtures among different species patch sizes at seeding. Integrating this knowledge into species interaction models in plant community ecology could greatly enhance our understanding of species coexistence in grasslands as well as provide opportunities for manipulating competition to achieve specific agronomic aims.}, journal={EUROPEAN JOURNAL OF AGRONOMY}, author={Ren, Haiyan and Cai, Anran and Rodrigues, Jorge L. Mazza and Wu, Xinwei and Wang, Lifeng and Chang, Jiechao and Wu, Xiuyang and Zhou, Quanping and Jiang, Yuehua and Hu, Shuijin}, year={2021}, month={Sep} }
 @article{xiao_ran_hu_guo_2021, title={The response of ammonia oxidizing archaea and bacteria in relation to heterotrophs under different carbon and nitrogen amendments in two agricultural soils}, volume={158}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2020.103812}, abstractNote={Ammonia-oxidizing archaea (AOA) and bacteria (AOB) drive nitrification and therefore critically modulate plant nitrogen (N) utilization, ecosystem N retention and environmental effects of reactive N. Previous studies have shown that abiotic factors (e.g., soil ammonium concentration, pH) can largely control the abundance and composition of ammonia oxidizers. However, whether the biotic factors, such as heterotrophic microbes play a role in impacting AOA and AOB remain unknown. Here, we conducted two experiments to assess the impacts of heterotrophs on AOA and AOB. First, a microcosm experiment was designed to create environments with different competition intensities between heterotrophic microbes and ammonia oxidizers through adding different amounts and ratios of organic C (cellulose) and mineral N [(NH4)2SO4] into two agriculture soils with long-term distinct fertilization histories. Along with the carbon to nitrogen (C/N) ratio gradient, rapid decreases in AOA and AOB abundances occurred accompanied with increased total microbial biomass and activities (respiration), suggesting intense competition between heterotrophic microbes and ammonia oxidizers. Pyrosequencing data revealed that different C/N ratios of substrate had significant impacts on the composition of the AOB but not on AOA communities. Second, to test whether there were inhibitive interactions through metabolic compounds, we examined the effect of water extracts of soils amended with high ratios of cellulose and ammonium sulfate on AOA /AOB abundances. The results showed that the extracts from substrates with C/N ratio of 50 and 100 reduced AOA and AOB abundance significantly, although this negative effect abated over time. Together, our findings indicate that both direct competition and inhibition by microbial metabolites critically affect AOA and AOB communities, providing new insights into the mechanisms that underlie ammonia oxidizer dynamics in agricultural ecosystems.}, journal={APPLIED SOIL ECOLOGY}, author={Xiao, Rui and Ran, Wei and Hu, Shuijin and Guo, Hui}, year={2021}, month={Feb} }
 @article{qiu_guo_xu_zhang_zhang_chen_zhao_burkey_shew_zobel_et al._2021, title={Warming and elevated ozone induce tradeoffs between fine roots and mycorrhizal fungi and stimulate organic carbon decomposition}, volume={7}, ISSN={["2375-2548"]}, DOI={10.1126/sciadv.abe9256}, abstractNote={Warming and elevated ozone alter root traits and mycorrhizal fungal community and stimulate organic carbon decomposition.}, number={28}, journal={SCIENCE ADVANCES}, author={Qiu, Yunpeng and Guo, Lijin and Xu, Xinyu and Zhang, Lin and Zhang, Kangcheng and Chen, Mengfei and Zhao, Yexin and Burkey, Kent O. and Shew, H. David and Zobel, Richard W. and et al.}, year={2021}, month={Jul} }
 @article{yan_diez_huang_li_luo_xu_su_jiang_guo_hu_2020, title={Beyond resource limitation: an expanded test of the niche dimension hypothesis for multiple types of niche axes}, volume={193}, ISSN={["1432-1939"]}, DOI={10.1007/s00442-020-04713-w}, number={3}, journal={OECOLOGIA}, author={Yan, Xuebin and Diez, Jeffrey and Huang, Kailing and Li, Shaopeng and Luo, Xi and Xu, Xinyu and Su, Fanglong and Jiang, Lin and Guo, Hui and Hu, Shuijin}, year={2020}, month={Jul}, pages={689–699} }
 @article{xiao_qiu_tao_zhang_chen_reberg-horton_shi_shew_zhang_hu_2020, title={Biological controls over the abundances of terrestrial ammonia oxidizers}, volume={29}, ISSN={["1466-8238"]}, DOI={10.1111/geb.13030}, abstractNote={AIM: Ammonia‐oxidizing archaea (AOA) and bacteria (AOB) are the primary agents for nitrification, converting ammonia (NH₄⁺) into nitrate (NO₃⁻) and modulating plant nitrogen (N) utilization and terrestrial N retention. However, there is still lack of a unifying framework describing the patterns of global AOA and AOB distribution. In particular, biotic interactions are rarely integrated into any of the conceptual models. LOCATION: World‐wide. TIME PERIOD: 2005–2016. MAJOR TAXA STUDIED: Ammonia‐oxidizing archaea and ammonia‐oxidizing bacteria. METHODS: A meta‐analysis and synthesis were conducted to obtain a general picture of global AOA and AOB distribution and identify the primary driving factors. A microcosm experiment was then conducted to assess effects of relative carbon to nitrogen availability for heterotrophic microbes on AOA and AOB in two distinct soils. A mesocosm experiment was further carried out to characterize the effects of plant roots and their arbuscular mycorrhizal fungi (AMF) on AOA and AOB abundances using hyphae‐ or root‐ingrowth techniques. RESULTS: Our meta‐analysis showed that soil carbon to nitrogen (C/N) ratios explained the most variance in AOA and AOB abundances, although soil pH had a significant effect. Experimental results demonstrated that high cellulose and mineral N inputs increased total microbial biomass and microbial activities, but inhibited AOA and AOB, suggesting microbial inhibition of AOA and AOB. Also, AMF and roots suppressed AOA and AOB, respectively. MAIN CONCLUSIONS: Our study provides convincing evidence illustrating that relative carbon to nitrogen availability can predominantly affect the abundances of AOA and AOB. Our experimental results further validate that biotic competition among plants, heterotrophic microbes and ammonia oxidizers for substrate N is the predominant control upon AOA and AOB abundances. Together, these findings provide new insights into the role of abiotic and biotic factors in modulating terrestrial AOA and AOB abundances and their potential applications for management of nitrification in an increasing reactive N world.}, number={2}, journal={GLOBAL ECOLOGY AND BIOGEOGRAPHY}, author={Xiao, Rui and Qiu, Yunpeng and Tao, Jinjin and Zhang, Xuelin and Chen, Huaihai and Reberg-Horton, S. Chris and Shi, Wei and Shew, H. David and Zhang, Yi and Hu, Shuijin}, year={2020}, month={Feb}, pages={384–399} }
 @article{long_zhang_liu_zhou_su_xiao_wang_guo_hu_2020, title={Can the scaling of plant nitrogen to phosphorus be altered by global change? An empirical test}, volume={13}, ISSN={["1752-993X"]}, DOI={10.1093/jpe/rtaa032}, abstractNote={Abstract Aims Global change may cause unparalleled supplies of soil nutrients and further lead to stoichiometric imbalance of nitrogen (N) and phosphorus (P) in terrestrial plants. While previous studies had reported the effects of global change factors on plant N, P contents and their ratios, few had examined whether or how these factors may influence the scaling of these two elements. Methods Taking advantage of a manipulative experiment with altered precipitation, warming and N addition, and using the general scaling function N = βPα, we examined how the scaling of plant N to P may respond to global change factors in a Loess grassland in northwestern China. Important Findings We found that precipitation reduction (PR) and warming decreased plant P concentrations, while N addition increased plant N concentrations, resulting in increased N:P ratios. The slopes of the linear regressions between plant N and P (i.e. log-transformed N versus P) did not change significantly, whereas the intercepts increased significantly under PR, warming and N addition. These results indicate that global change factors may not affect the synergistic variation of plant N and P, showing a closely coupled relationship between them. Our findings may help to better understand plant nutrient dynamics and element balance in a changing world.}, number={4}, journal={JOURNAL OF PLANT ECOLOGY}, author={Long, Min and Zhang, Juanjuan and Liu, Zhengyi and Zhou, Luyao and Su, Fanglong and Xiao, Rui and Wang, Yi and Guo, Hui and Hu, Shuijin}, year={2020}, month={Aug}, pages={442–449} }
 @article{fowler_denning_hu_watson_schmidt_2020, title={Carbon Neutral: The Failure of Dung Beetles (Coleoptera: Scarabaeidae) to Affect Dung-Generated Greenhouse Gases in the Pasture}, volume={49}, ISSN={["1938-2936"]}, DOI={10.1093/ee/nvaa094}, abstractNote={Abstract Research suggests dung beetles can churn, aerate, and desiccate dung in ways that influence the dung and soil microbes producing greenhouse gases (GHGs). We examined the impacts of the tunneling beetle, Onthophagus taurus (Schreber), and the dwelling beetle, Labarrus pseudolividus (Balthasar), on the carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emitted from pasture-laid bovine dung as well as their sum-total (CO2 + CH4 + N2O) effect on global warming, or their carbon dioxide equivalent (CO2e). Despite dung beetles potential effects on CH4 and N2O, the existing literature shows no ultimate CO2e reductions. We hypothesized that more dung beetles would degrade pats faster and reduce CO2e, and so we increased the average dung beetle biomass per dung volume 6.22× above previously published records, and visually documented any dung damage. However, the time effects were 2–5× greater for any GHG and CO2e (E = 0.27–0.77) than dung beetle effects alone (E = 0.09–0.24). This suggests that dung beetle communities cannot adequately reduce GHGs unless they can accelerate dung decomposition faster than time alone.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Fowler, Fallon and Denning, Steve and Hu, Shuijin and Watson, Wes and Schmidt, Jason}, year={2020}, month={Oct}, pages={1105–1116} }
 @article{zhang_zhang_yin_yang_zhao_jiang_tao_yan_qiu_guo_et al._2020, title={Combination of warming and N inputs increases the temperature sensitivity of soil N2O emission in a Tibetan alpine meadow}, volume={704}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2019.135450}, abstractNote={Many high-elevation alpine ecosystems have been experiencing significant increases in air temperature and, to a lesser extent, nitrogen (N) deposition. These changes may affect N-cycling microbes and enhance emissions of nitrous oxide (N2O, a potent greenhouse gas) from soil. However, few studies have investigated whether and how the resulting changes in N-cycling microbes may affect the temperature sensitivity (Q10) of N2O emission and in turn feed back to N2O emissions. We conducted two incubation experiments to examine N2O emissions and their temperature sensitivities in soils that had experienced 3-yr field treatments of warming, N inputs and their combination in a Tibetan alpine meadow. Our results showed that neither N inputs nor warming alone affected the rate or Q10 of soil N2O emission, but combining the two significantly increased both parameters. Also, combined N and warming significantly increased the abundance of ammonia-oxidizing bacteria (AOB), corresponding with high soil N2O emission. In addition, N2O emission from nitrification accounted for 60-80% of total emissions in all soils, indicating that nitrifying microbes dominated the N2O production and its temperature sensitivity. Using random forest (RF) and structural equation model (SEM) analyses, we further evaluated the effects of various soil characteristics on soil N2O emissions and Q10. We identified soil moisture, pH, N mineralization and AOB abundance as the main predictors of the Q10 of N2O emissions. Together, these findings suggest that alterations in soil moisture, pH and ammonia-oxidizing bacteria induced by long-term N inputs and warming may increase temperature sensitivity of soil N2O emissions, leading to a positive climate feedback in this high-altitude alpine ecosystem.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Zhang, Yi and Zhang, Nan and Yin, Jingjing and Yang, Fei and Zhao, Yexin and Jiang, Zhongquan and Tao, Jinjin and Yan, Xuebin and Qiu, Yunpeng and Guo, Hui and et al.}, year={2020}, month={Feb} }
 @article{jiang_jiang_zhang_su_tian_wang_sun_nong_hu_wang_et al._2020, title={Contrasting the Pb (II) and Cd (II) tolerance of Enterobacter sp. via its cellular stress responses}, volume={22}, ISSN={["1462-2920"]}, DOI={10.1111/1462-2920.14719}, abstractNote={Successful application of microorganisms to heavy metal remediation depends on their resistance to toxic metals. This study contrasted the differences of tolerant mechanisms between Pb2+ and Cd2+ in Enterobacter sp. Microbial respiration and production of formic acid showed that Enterobacter sp. had a higher tolerant concentration of Pb (>1000 mg l-1 ) than Cd (about 200 mg l-1 ). Additionally, SEM confirmed that most of Pb and Cd nanoparticles (NPs) were adsorbed onto cell membrane. The Cd stress, even at low concentration (50 mg l-1 ), significantly enlarged the sizes of cells. The cellular size raised from 0.4 × 1.0 to 0.9 × 1.6 μm on average, inducing a platelet-like shape. In contrast, Pb cations did not stimulate such enlargement even up to 1000 mg l-1 . Moreover, Cd NPs were adsorbed homogeneously by almost all the bacterial cells under TEM. However, only a few cells work as 'hot spots' on the sorption of Pb NPs. The heterogeneous sorption might result from a 'self-sacrifice' mechanism, i.e., some cells at a special life stage contributed mostly to Pb sorption. This mechanism, together with the lower mobility of Pb cations, caused higher microbial tolerance and removal efficiency towards Pb2+ . This study sheds evident contrasts of bacterial resistance to the two most common heavy metals.}, number={4}, journal={ENVIRONMENTAL MICROBIOLOGY}, author={Jiang, Zhongquan and Jiang, Liu and Zhang, Lin and Su, Mu and Tian, Da and Wang, Tong and Sun, Yalin and Nong, Ying and Hu, Shuijin and Wang, Shimei and et al.}, year={2020}, month={Apr}, pages={1507–1516} }
 @article{wang_huang_hu_2020, title={Distinct fine-root responses to precipitation changes in herbaceous and woody plants: a meta-analysis}, volume={225}, ISSN={["1469-8137"]}, DOI={10.1111/nph.16266}, abstractNote={Precipitation is one of the most important factors that determine productivity of terrestrial ecosystems. Precipitation across the globe is predicted to change more intensively under future climate change scenarios, but the resulting impact on plant roots remains unclear. Based on 154 observations from experiments in which precipitation was manipulated in the field and root biomass was measured, we investigated responses in fine-root biomass of herbaceous and woody plants to alterations in precipitation. We found that root biomass of herbaceous and woody plants responded differently to precipitation change. In particular, precipitation increase consistently enhanced fine-root biomass of woody plants but had variable effects on herb roots in arid and semi-arid ecosystems. In contrast, precipitation decrease reduced root biomass of herbaceous plants but not woody plants. In addition, with precipitation alteration, the magnitude of root responses was greater in dry areas than in wet areas. Together, these results indicate that herbaceous and woody plants have different rooting strategies to cope with altered precipitation regimes, particularly in water-limited ecosystems. These findings suggest that root responses to precipitation change may critically influence root productivity and soil carbon dynamics under future climate change scenarios.}, number={4}, journal={NEW PHYTOLOGIST}, author={Wang, Peng and Huang, Kailing and Hu, Shuijin}, year={2020}, month={Feb}, pages={1491–1499} }
 @article{wu_wu_saleem_wang_hu_bai_pan_chen_2020, title={Ecological clusters based on responses of soil microbial phylotypes to precipitation explain ecosystem functions}, volume={142}, ISSN={["1879-3428"]}, DOI={10.1016/j.soilbio.2020.107717}, abstractNote={Ecological classification has been proposed as a way to more tightly link microbial communities and ecosystem functions, but few studies have attempted to relate ecological classifications of microbial communities with specific ecosystem functions. Here, we conducted a 3-year experiment with nine levels of artificial precipitation (100–500 mm) in a typical semi-arid steppe. The first five levels (≤300 mm) were considered a “dry” gradient, and the last five (≥300 mm) were considered a “wet” gradient. Increases in precipitation under dry and wet gradients did not alter the alpha diversities of soil bacterial, soil fungal, or plant communities, except that increases in precipitation under the dry gradient decreased bacterial alpha diversity. Increases in precipitation under the dry and wet gradients altered the composition of the soil bacterial community but did not alter the composition of the fungal or plant communities. Ecological clusters (ECs) based on the relationships between the relative abundance of phylotypes and dry and wet gradients were correlated with soil C or N mineralization rates; these ECs explained 14–28% of the total variance in soil C and N mineralization rates. In contrast, soil C or N mineralization rates were not correlated with the commonly measured properties (e.g., biomass and diversity) of plant, soil bacterial, and soil fungal communities. Our findings indicate that the grouping of soil microorganisms into ECs based on responses to precipitation gradients can provide insights into the relationships between soil organisms and ecosystem functions.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Wu, Ying and Wu, Jianping and Saleem, Muhammad and Wang, Bing and Hu, Shuijin and Bai, Yongfei and Pan, Qingmin and Chen, Dima}, year={2020}, month={Mar} }
 @article{wang_wu_chen_wu_hu_li_bai_2020, title={Grazing simplifies soil micro-food webs and decouples their relationships with ecosystem functions in grasslands}, volume={26}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.14841}, abstractNote={Livestock grazing often alters aboveground and belowground communities of grasslands and their mediated carbon (C) and nitrogen (N) cycling processes at the local scale. Yet, few have examined whether grazing-induced changes in soil food webs and their ecosystem functions can be extrapolated to a regional scale. We investigated how large herbivore grazing affects soil micro-food webs (microbes and nematodes) and ecosystem functions (soil C and N mineralization), using paired grazed and ungrazed plots at 10 locations across the Mongolian Plateau. Our results showed that grazing not only affected plant variables (e.g., biomass and C and N concentrations), but also altered soil substrates (e.g., C and N contents) and soil environment (e.g., soil pH and bulk density). Grazing had strong bottom-up effects on soil micro-food webs, leading to more pronounced decreases at higher trophic levels (nematodes) than at lower trophic levels (microbes). Structural equation modeling showed that changes in plant biomass and soil environment dominated grazing effects on microbes, while nematodes were mainly influenced by changes in plant biomass and soil C and N contents; the grazing effects, however, differed greatly among functional groups in the soil micro-food webs. Grazing reduced soil C and N mineralization rates via changes in plant biomass, soil C and N contents, and soil environment across grasslands on the Mongolian Plateau. Spearman's rank correlation analysis also showed that grazing reduced the correlations between functional groups in soil micro-food webs and then weakened the correlation between soil micro-food webs and soil C and N mineralization. These results suggest that changes in soil micro-food webs resulting from livestock grazing are poor predictors of soil C and N processes at regional scale, and that the relationships between soil food webs and ecosystem functions depend on spatial scales and land-use changes.}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Wang, Bing and Wu, Liji and Chen, Dima and Wu, Ying and Hu, Shuijin and Li, Linghao and Bai, Yongfei}, year={2020}, month={Feb}, pages={960–970} }
 @article{zhao_guo_shu_wang_hu_2020, title={Impacts of drought and nitrogen enrichment on leaf nutrient resorption and root nutrient allocation in four Tibetan plant species}, volume={723}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2020.138106}, abstractNote={Plant nutrient resorption, a process by which plant withdraws nutrients from senescing structures to developing tissues, can significantly affect plant growth, litter decomposition and nutrient cycling. Global change factors, such as nitrogen (N) deposition and altered precipitation, may mediate plant nutrient resorption and allocation. The ongoing global change is accompanied with increased N inputs and drought frequency in many regions. However, the interactive effects of increased N availability and drought on plant nutrient-responses remain largely unclear. In a pot experiment, we examined the impacts of N enrichment and drought on leaf N and phosphorous (P) resorption and root nutrient allocation in four species from the Qinghai-Tibet Plateau, including two graminoid species (Kobresia capillifolia and Elymus nutans) and two forb species (Delphinium kamaonense and Aster diplostephioides). Our results showed divergent resorption patterns within the two functional groups. E. nutans and D. kamaonense showed stronger N resorption than K. capillifolia and A. diplostephioides. N addition did not alter their N resorption efficiencies, but decreased the N resorption proficiencies of the former two species. In contrast, drought did not affect N or P resorption proficiencies, but decreased N resorption efficiency of K. capillifolia. Besides, N addition facilitated P resorption in K. capillifolia and D. kamaonense, and drought did the same in A. diplostephioides, suggesting that P resorption plays an important role in nutrient conservation in these species. Moreover, species with stronger N resorption allocated more biomass C or N to aboveground and enhanced their litter quality under N enrichment, while species with weaker resorption allocated more biomass C and/or N to belowground part under drought. Together, these results show that the responses of nutrient resorption and allocation to N enrichment and drought are highly species-specific. Future studies should take these differential responses into consideration to better predict litter decomposition and ecosystem nutrient cycling.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Zhao, Qingzhou and Guo, Jin and Shu, Meng and Wang, Peng and Hu, Shuijin}, year={2020}, month={Jun} }
 @article{bai_wang_hall_wang_ye_li_li_zhou_qiu_guo_et al._2020, title={Interactive global change factors mitigate soil aggregation and carbon change in a semi-arid grassland}, volume={26}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.15220}, abstractNote={The ongoing global change is multi-faceted, but the interactive effects of multiple drivers on the persistence of soil carbon (C) are poorly understood. We examined the effects of warming, reactive nitrogen (N) inputs (12 g N m−2 year−1) and altered precipitation (+ or − 30% ambient) on soil aggregates and mineral-associated C in a 4 year manipulation experiment with a semi-arid grassland on China's Loess Plateau. Our results showed that in the absence of N inputs, precipitation additions significantly enhanced soil aggregation and promoted the coupling between aggregation and both soil fungal biomass and exchangeable Mg2+. However, N inputs negated the promotional effects of increased precipitation, mainly through suppressing fungal growth and altering soil pH and clay-Mg2+-OC bridging. Warming increased C content in the mineral-associated fraction, likely by increasing inputs of root-derived C, and reducing turnover of existing mineral-associated C due to suppression of fungal growth and soil respiration. Together, our results provide new insights into the potential mechanisms through which multiple global change factors control soil C persistence in arid and semi-arid grasslands. These findings suggest that the interactive effects among global change factors should be incorporated to predict the soil C dynamics under future global change scenarios.}, number={9}, journal={GLOBAL CHANGE BIOLOGY}, author={Bai, Tongshuo and Wang, Peng and Hall, Steven J. and Wang, Fuwei and Ye, Chenglong and Li, Zhen and Li, Shijie and Zhou, Luyao and Qiu, Yunpeng and Guo, Jiuxin and et al.}, year={2020}, month={Sep}, pages={5320–5332} }
 @article{xu_zhang_zhu_xiao_zhu_zhang_yu_li_zhu_tu_et al._2020, title={Large losses of ammonium-nitrogen from a rice ecosystem under elevated CO2}, volume={6}, ISSN={["2375-2548"]}, DOI={10.1126/sciadv.abb7433}, abstractNote={Inputs of nitrogen into terrestrial ecosystems, mainly via the use of ammonium-based fertilizers in agroecosystems, are enormous, but the fate of this nitrogen under elevated atmospheric carbon dioxide (CO2) is not well understood. We have taken advantage of a 15-year free-air CO2 enrichment study to investigate the influence of elevated CO2 on the transformation of ammonium-nitrogen in a rice ecosystem in which ammonium is usually assumed to be stable under anaerobic conditions. We demonstrate that elevated CO2 causes substantial losses of ammonium-nitrogen that result from anaerobic oxidation of ammonium coupled to reduction of iron. We identify a new autotrophic member of the bacterial order Burkholderiales that may use soil CO2 as a carbon source to couple anaerobic ammonium oxidation and iron reduction. These findings offer insight into the coupled cycles of nitrogen and iron in terrestrial ecosystems and raise questions about the loss of ammonium-nitrogen from arable soils under future climate-change scenarios.}, number={42}, journal={SCIENCE ADVANCES}, author={Xu, Chenchao and Zhang, Kaihang and Zhu, Wanying and Xiao, Jing and Zhu, Chen and Zhang, Naifang and Yu, Fangjian and Li, Shuyao and Zhu, Chunwu and Tu, Qichao and et al.}, year={2020}, month={Oct} }
 @article{li_wang_chen_liu_zhou_deng_dong_bao_bai_li_et al._2020, title={Mowing alters nitrogen effects on the community-level plant stoichiometry through shifting plant functional groups in a semi-arid grassland}, volume={15}, ISSN={["1748-9326"]}, DOI={10.1088/1748-9326/ab8a87}, abstractNote={Abstract Land-use practices such as mowing and nitrogen (N) fertilization can have significant impacts on plant stoichiometry. However, the interactive effects of mowing and N fertilization on the community-level plant stoichiometry and the underlying processes are not well understood. We examined the impacts of mowing (once a year) and N fertilization (12 g N m −2 yr −1 ) on the community-level plant stoichiometry in a semi-arid grassland on the Loess Plateau. Results obtained showed that mowing alone had no effect on the community-level plant N or phosphorus (P) concentration. N fertilization alone significantly reduced the community-level plant P concentration, but did not affect the community-level plant N concentration, leading to an enhancement of plant N:P ratio. However, mowing altered the effects of N fertilization, leading to a higher plant N (and P) concentration than the fertilization-only plots. Also, mowing significantly reduced soil nitrate (NO 3 − ), but increased soil temperature, photosynthetic active radiation, plant diversity, richness and gross ecosystem productivity. In addition, mowing and N fertilization significantly affected plant community composition through shifting dominant plant functional groups (PFGs) (e.g. asteraceae, forbs and grass). Further, our structural equation modeling analysis showed that shifts in PFGs played an important role in regulating plant stoichiometry under mowing and N fertilization. Together, these results illustrate that effective management of mowing and N fertilization may induce changes in soil limiting nutrients and shifts in plant community composition, potentially altering plant N:P stoichiometry at the community level.}, number={7}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Li, Shijie and Wang, Fuwei and Chen, Mengfei and Liu, Zhengyi and Zhou, Luyao and Deng, Jun and Dong, Changjun and Bao, Guocheng and Bai, Tongshuo and Li, Zhen and et al.}, year={2020}, month={Jul} }
 @article{yang_zhou_weih_li_zhai_zhang_chen_liu_liu_hu_2020, title={Mycorrhizal nitrogen uptake of wheat is increased by earthworm activity only under no-till and straw removal conditions}, volume={155}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2020.103672}, abstractNote={A large part of crop nutrient uptake occurs through the interaction of roots with symbiotic arbuscular mycorrhizal fungi (AMF). However, it is still an open question how straw management and earthworm activity affect AMF community structure and their nitrogen-transferring function in wheat. A split-plot field experiment was conducted to address this question. Three straw management regimes including different tillage treatments (no-till with no straw, NTNS; rotary tillage with straw return, RTSR and ditch-buried straw return, DBSR), and two earthworm treatments (no earthworm, −E; and earthworm addition, +E) were conducted. The AMF community structure in the wheat roots was characterized with high-throughput sequencing, and its function in terms of N acquisition was measured with 15N isotope tracing through hyphal in-growth cores. Our results showed that both the DBSR and RTSR treatments significantly changed AMF community composition and enhanced the mycorrhiza-mediated plant N uptake when compared to NTNS. The effect of earthworm activity on AMF community composition and mycorrhiza-mediated N uptake strongly depended on the straw management regimes. While earthworm presence increased AMF dominance (+32.9%) and mycorrhizal N uptake (+2.05-fold) under straw removal, they decreased AMF dominance (−30.4% and −41.9% respectively) and mycorrhizal N uptake (−37.3% and −34.3% respectively) under both DBSR and RTSR treatments in comparison with the absence of earthworms. It is concluded that straw addition shifts the AMF community structure and increases N uptake by the host plants; and that the effect of earthworms on AMF community structure and functioning depends on the straw management regime. The results suggest that straw management and its interaction with earthworms can affect mycorrhiza-mediated plant N uptake, possibly through altering some dominant AMF taxa.}, journal={APPLIED SOIL ECOLOGY}, author={Yang, Haishui and Zhou, Jiajia and Weih, Martin and Li, Yifan and Zhai, Silong and Zhang, Qian and Chen, Weiping and Liu, Jian and Liu, Ling and Hu, Shuijin}, year={2020}, month={Nov} }
 @misc{cheng_wang_wang_wang_chang_cai_zhang_niu_hu_2020, title={Nitrogen deposition differentially affects soil gross nitrogen transformations in organic and mineral horizons}, volume={201}, ISSN={["1872-6828"]}, DOI={10.1016/j.earscirev.2019.103033}, abstractNote={Abstract Reactive nitrogen (N) input can profoundly alter soil N transformations and long-term productivity of forest ecosystems. However, critical knowledge gaps exist in our understanding of N deposition effects on internal soil N cycling in forest ecosystems. It is well established that N addition enhances soil N availability based on traditional net mineralization rate assays. Yet, experimental additions of inorganic N to soils broadly show a suppression of microbial activity and protein depolymerization. Here we show, from a global meta-analysis of 15N-labelled studies that gross N transformation rates in forest soil organic and mineral horizons differentially respond to N addition. In carbon (C)-rich organic horizons, N addition significantly enhanced soil gross rates of N mineralization, nitrification and microbial NO3¯ immobilization rates, but decreased gross microbial NH4+ immobilization rates. In C-poor mineral soils, in contrast, N addition did not change gross N transformation rates except for increasing gross nitrification rates. An initial soil C/N threshold of approx. 14.6, above which N addition enhanced gross N mineralization rates, could explain why gross N mineralization was increased by N deposition in organic horizons alone. Enhancement of gross N mineralization by N deposition was also largely attributed to enhanced N mineralization activity per unit microbial biomass. Our results indicate that the net effect of N input on forest soil gross N transformations are highly stratified by soil C distribution along the soil profile, and thus challenge the perception that N availability ubiquitously limits N mineralization. These findings suggest that these differences should be integrated into models to better predict forest ecosystem N cycle and C sequestration potential under future N deposition scenarios.}, journal={EARTH-SCIENCE REVIEWS}, author={Cheng, Yi and Wang, Jing and Wang, Jinyang and Wang, Shenqiang and Chang, Scott X. and Cai, Zucong and Zhang, Jinbo and Niu, Shuli and Hu, Shuijin}, year={2020}, month={Feb} }
 @article{pan_wang_qiu_chen_zhang_ye_guo_zhu_chen_xu_et al._2020, title={Nitrogen-induced acidification, not N-nutrient, dominates suppressive N effects on arbuscular mycorrhizal fungi}, volume={26}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.15311}, abstractNote={Arbuscular mycorrhizal fungi (AMF) form symbiosis with most terrestrial plant roots, obtaining photosynthates in return for mineral nutrients. Ecological theories based on the economics of trading partnership predict that nutrient enrichment would suppress AMF. Experimental results from nitrogen (N) and phosphorus (P) additions, however, were highly variable, and the underlying mechanisms remain unclear. Here we show distinct AMF responses to soil N:P stoichiometry manipulations via gradients of long‐term N and P additions in a Mongolian steppe. A complementary experiment with an acid addition gradient was designed to help tease apart the effect of N‐induced acidification from N nutrient. AMF root colonization and extraradical fungal biomass progressively decreased along the P gradient under two distinct host plant species, suggesting a carbon (C)‐P tradeoff. In contrast, low to moderate N inputs increased both AMF parameters, corresponding to the increasing N:P ratio. Yet, high N inputs reduced AMF colonization and biomass, and the magnitudes of N‐led inhibition were similar to those under acid additions that induced comparable changes in soil pH. Structural equation modeling further showed that while soil N:P stoichiometry primarily controlled the effect of P addition on AMF, N‐induced soil acidity overtook the N:P stoichiometry under high N inputs and dominated the effects of reactive N on AMF. In addition, AMF community composition in roots was more dependent on host plants and unresponsive to changes in soil nutrients. We further proposed a comprehensive framework that integrates biological and geochemical effects of reactive N and P inputs on AMF. Together, these results indicate that while the C‐P tradeoff controls P suppression of AMF, N‐induced acidification dominates the N inhibition. Our findings suggest that incorporation of geochemical impacts of N and P inputs would facilitate modeling efforts to project mycorrhizal impact on plant interactions and soil C balance under future nutrient enrichment scenarios.}, number={11}, journal={GLOBAL CHANGE BIOLOGY}, author={Pan, Shang and Wang, Yang and Qiu, Yunpeng and Chen, Dima and Zhang, Lin and Ye, Chenglong and Guo, Hui and Zhu, Weixing and Chen, Aiqun and Xu, Guohua and et al.}, year={2020}, month={Nov}, pages={6568–6580} }
 @article{su_wang_li_wei_li_bai_wang_guo_hu_2020, title={Predominant role of soil moisture in regulating the response of ecosystem carbon fluxes to global change factors in a semi-arid grassland on the Loess Plateau}, volume={738}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2020.139746}, abstractNote={Climate warming, altered precipitation and nitrogen deposition may critically affect plant growth and ecosystem carbon fluxes. However, the underlying mechanisms are not fully understood. We conducted a 2-yr, multi-factor experiment (warming (W), altered precipitation (+30% and − 30%) and nitrogen addition (N)) in a semi-arid grassland on the Loess Plateau to study how these factors affect ecosystem carbon fluxes. Surprisingly, no interactive effects of warming, altered precipitation and nitrogen addition were detected on parameters of ecosystem carbon fluxes, including net ecosystem CO2 exchange (NEE), ecosystem respiration (ER), gross ecosystem productivity (GEP) and soil respiration (SR). Warming marginally reduced NEE and GEP mainly due to its negative effects on them in July and August. Altered precipitation significantly affected all parameters of carbon fluxes with precipitation reduction decreasing NEE, ER and GEP, whereas precipitation addition increasing SR. In contrast, nitrogen addition had little effect on any parameters of carbon fluxes. Soil moisture was the most important driver and positively correlated with ecosystem carbon fluxes and warming impacted ecosystem carbon fluxes indirectly by decreasing soil moisture. While plant community cover did not show significant association with carbon fluxes, semi-shrubs cover was positively related to NEE, ER and GEP. Together, these results suggest that soil water availability, rather than soil temperature and nitrogen availability, may dominate the effect of the future multi-faceted global changes on semi-arid grassland carbon fluxes on the Loess Plateau.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Su, Fanglong and Wang, Fuwei and Li, Zhen and Wei, Yanan and Li, Shijie and Bai, Tongshuo and Wang, Yi and Guo, Hui and Hu, Shuijin}, year={2020}, month={Oct} }
 @article{zhang_zhang_yin_zhao_yang_jiang_tao_yan_qiu_guo_et al._2020, title={Simulated warming enhances the responses of microbial N transformations to reactive N input in a Tibetan alpine meadow}, volume={141}, ISSN={["1873-6750"]}, DOI={10.1016/j.envint.2020.105795}, abstractNote={Abstract Alpine ecosystems worldwide are characterized with high soil organic carbon (C) and low mineral nitrogen (N). Climate warming has been predicted to stimulate microbial decomposition and N mineralization in these systems. However, experimental results are highly variable, and the underlying mechanisms remain unclear. We examined the effects of warming, N input, and their combination on soil N pools and N-cycling microbes in a field manipulation experiment. Special attention was directed to the ammonia-oxidizing bacteria and archaea, and their mediated N-cycling processes (transformation rates and N2O emissions) in the third plant growing season after the treatments were initiated. Nitrogen input (12 g m−2 y−1) alone significantly increased soil mineral N pools and plant N uptake, and stimulated the growth of AOB and N2O emissions in the late growing season. While warming (by 1.4 °C air temperature) alone did not have significant effects on most parameters, it amplified the effects of N input on soil N concentrations and AOB abundance, eliciting a chain reaction that increased nitrification potential (+83%), soil NO3−-N (+200%), and N2O emissions (+412%) across the whole season. Also, N input reduced AOB diversity but increased the dominance of genus Nitrosospira within the AOB community, corresponding to the increased N2O emissions. These results showed that a small temperature increase in soil may significantly enhance N losses through NO3− leaching and N2O emissions when mineral N becomes available. These findings suggest that interactions among global change factors may predominantly affect ammonia-oxidizing microbes and their mediated N-cycling processes in alpine ecosystems under future climate change scenarios.}, journal={ENVIRONMENT INTERNATIONAL}, author={Zhang, Yi and Zhang, Nan and Yin, Jingjing and Zhao, Yexin and Yang, Fei and Jiang, Zhongquan and Tao, Jinjin and Yan, Xuebin and Qiu, Yunpeng and Guo, Hui and et al.}, year={2020}, month={Aug} }
 @article{wang_guo_xu_yan_zhang_qiu_zhao_huang_luo_yang_et al._2020, title={Soil acidification alters root morphology, increases root biomass but reduces root decomposition in an alpine grassland}, volume={265}, ISSN={["1873-6424"]}, DOI={10.1016/j.envpol.2020.115016}, abstractNote={Soil acidification has been expanding in many areas of Asia due to increasing reactive nitrogen (N) inputs and industrial activities. While the detrimental effects of acidification on forests have been extensively studied, less attention has been paid to grasslands, particularly alpine grasslands. In a soil pH manipulation experiment in the Qinghai-Tibet Plateau, we examined the effects of soil acidification on plant roots, which account for the major part of alpine plants. After three years of manipulation, soil pH decreased from 6.0 to 4.7 with the acid-addition gradient, accompanied by significant changes in the availability of soil nitrogen, phosphorus and cations. Plant composition shifted with the soil acidity, with graminoids replacing forbs. Differing from findings in forests, soil acidification in the alpine grassland increased root biomass by increasing the fraction of coarse roots and the production of fine roots, corresponding to enhanced sedge and grass biomass, respectively. In addition, litter decomposability decreased with altered root morphological and chemical traits, and soil acidification slowed root decomposition by reducing soil microbial activity and litter quality. Our results showed that acidification effect on root dynamics in our alpine grassland was significantly different from that in forests, and supported similar results obtained in limited studies in other grassland ecosystems. These results suggest an important role of root morphology in mediating root dynamics, and imply that soil acidification may lead to transient increase in soil carbon stock as root standing biomass and undecomposed root litter. These changes may reduce nutrient cycling and further constrain ecosystem productivity in nutrient-limiting alpine systems.}, journal={ENVIRONMENTAL POLLUTION}, author={Wang, Peng and Guo, Jin and Xu, Xinyu and Yan, Xuebin and Zhang, Kangcheng and Qiu, Yunpeng and Zhao, Qingzhou and Huang, Kailing and Luo, Xi and Yang, Fei and et al.}, year={2020}, month={Oct} }
 @article{xiao_wang_lu_chen_wu_zhu_hu_bai_2020, title={Soil acidification reduces the effects of short-term nutrient enrichment on plant and soil biota and their interactions in grasslands}, volume={26}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.15167}, abstractNote={Soil nitrogen (N) and phosphorus (P) contents, and soil acidification have greatly increased in grassland ecosystems due to increased industrial and agricultural activities. As major environmental and economic concerns worldwide, nutrient enrichment and soil acidification can lead to substantial changes in the diversity and structure of plant and soil communities. Although the separate effects of N and P enrichment on soil food webs have been assessed across different ecosystems, the combined effects of N and P enrichment on multiple trophic levels in soil food webs have not been studied in semiarid grasslands experiencing soil acidification. Here we conducted a short-term N and P enrichment experiment in non-acidified and acidified soil in a semiarid grassland on the Mongolian Plateau. We found that net primary productivity was not affected by N or P enrichment alone in either non-acidified or acidified soil, but was increased by combined N and P enrichment in both non-acidified and acidified soil. Nutrient enrichment decreased the biomass of most microbial groups in non-acidified soil (the decrease tended to be greatest with combined N and P enrichment) but not in acidified soil, and did not affect most soil nematode variables in non-acidified or acidified soil. Nutrient enrichment also changed plant and microbial community structure in non-acidified but not in acidified soil, and had no effect on nematode community structure in non-acidified or acidified soil. These results indicate that the responses to short-term nutrient enrichment were weaker for higher trophic groups (nematodes) than for lower trophic groups (microorganisms) and primary producers (plants). The findings increase our understanding of the effects of nutrient enrichment on multiple trophic levels of soil food webs, and highlight that soil acidification, as an anthropogenic stressor, reduced the responses of plants and soil food webs to nutrient enrichment and weakened plant–soil interactions.}, number={8}, journal={GLOBAL CHANGE BIOLOGY}, author={Xiao, Hong and Wang, Bing and Lu, Shunbao and Chen, Dima and Wu, Ying and Zhu, Yuhe and Hu, Shuijin and Bai, Yongfei}, year={2020}, month={Aug}, pages={4626–4637} }
 @article{tian_jiang_jiang_su_feng_zhang_wang_li_hu_2019, title={A new insight into lead (II) tolerance of environmental fungi based on a study of Aspergillus niger and Penicillium oxalicum}, volume={21}, ISSN={["1462-2920"]}, DOI={10.1111/1462-2920.14478}, abstractNote={Environmental microorganisms have been widely applied in heavy metal remediation. This study explored the mechanisms of lead tolerance of two typical filamentous fungi, Aspergillus niger and Penicillium oxalicum. It is shown that the mechanisms of reducing Pb toxicity by these two fungi have three major pathways. The secreted oxalic acid can react with Pb (II) to form insoluble Pb minerals, primarily lead oxalate. Then, the enhanced biosorption via forming new border of cell wall prevents the transportation of Pb (II) into hypha. In addition, the fungal activity could be maintained even at high Pb concentration due to the intracellular accumulation. It was confirmed that A. niger has the higher Pb tolerance (up to 1500 mg l-1 Pb level) compared with P. oxalicum (up to 1000 mg l-1 ). Meanwhile, Pb levels below 1000 mg l-1 partially stimulate the bioactivity of A. niger, which was confirmed by its elevated respiration (from 53 to 63 mg C l-1 medium h-1 ). This subsequently enhanced microbial functions of A. niger to resist Pb toxicity. A better understanding of Pb tolerance of these two fungi sheds a bright future of applying them to remediate lead-contaminated environments.}, number={1}, journal={ENVIRONMENTAL MICROBIOLOGY}, author={Tian, Da and Jiang, Zhongquan and Jiang, Liu and Su, Mu and Feng, Zheye and Zhang, Lin and Wang, Shimei and Li, Zhen and Hu, Shuijin}, year={2019}, month={Jan}, pages={471–479} }
 @article{ye_hall_hu_2019, title={Controls on mineral-associated organic matter formation in a degraded Oxisol}, volume={338}, ISSN={["1872-6259"]}, DOI={10.1016/j.geoderma.2018.12.011}, abstractNote={Oxisols are the dominant soil type in humid tropical and subtropical regions and are subjected to both drying–rewetting (DRW) cycles and fluctuating oxygen (O2) availability driven by warm temperatures and abundant rainfall in surface layers. Drying-rewetting cycles and O2 fluctuations may critically affect the microbial transformation of plant litter and subsequent stabilization as mineral-associated organic carbon (MAOC), but experimental data are still limited. We examined the impacts of DRW cycles, and variable O2 regimes with constant moisture, on carbon (C) and iron (Fe) dynamics in a degraded Oxisol (under long-term fallow) with added plant residues. In laboratory incubations (>3 months), both DRW cycling and fluctuating O2 availability induced a flush of respiration and a temporary increase in microbial biomass C (MBC) following soil rewetting or O2 exposure, although MBC was consistently suppressed in these treatments relative to the control (60% water holding capacity under constantly aerobic condition). Consequently, DRW cycles significantly increased but O2 fluctuations significantly decreased cumulative C mineralization relative to the control. Concentrations of short-range-ordered Fe oxides peaked immediately after litter addition and decreased five-fold during the remainder of the experiment. Mineral-associated C (defined as the chemically dispersed <53 μm soil fraction) increased 42–64% relative to initial values but was significantly lower under DRW cycling and fluctuating O2 relative to the control. Correspondingly, these treatments had greater fine particulate organic C (53–250 μm), despite increased CO2 production under DRW cycling. Our data indicate the potential for rapid and significant accrual of MAOC in a degraded Oxisol, but environmental factors such as DRW cycling and fluctuating O2 can inhibit the conversion of plant litter to MAOC—possibly by suppressing microbial biomass formation and/or microbial transformations of organic matter.}, journal={GEODERMA}, author={Ye, Chenglong and Hall, Steven J. and Hu, Shuijin}, year={2019}, month={Mar}, pages={383–392} }
 @article{yang_niu_collins_yan_ji_ling_zhou_du_guo_hu_2019, title={Cover Image}, volume={30}, ISSN={1085-3278}, url={http://dx.doi.org/10.1002/LDR.3244}, DOI={10.1002/LDR.3244}, number={1}, journal={Land Degradation & Development}, publisher={Wiley}, author={Yang, Fei and Niu, Kechang and Collins, Courtney G. and Yan, Xuebin and Ji, Yangguang and Ling, Ning and Zhou, Xianhui and Du, Guozhen and Guo, Hui and Hu, Shuijin}, year={2019}, month={Jan}, pages={i-i} }
 @article{bai_tao_li_shu_yan_wang_ye_guo_wang_hu_2019, title={Different microbial responses in top- and sub-soils to elevated temperature and substrate addition in a semiarid grassland on the Loess Plateau}, volume={70}, ISSN={["1365-2389"]}, DOI={10.1111/ejss.12800}, abstractNote={The Loess Plateau soil in northwest China originated from wind sediments and is characterized by deep soil profiles and large organic carbon (C) content. Severe soil erosion constantly exposes deep soils to the surface, making the organic C vulnerable to microbial decomposition. Few, however, have so far examined how soil microbial activity and community composition in the deep loess soil respond to perturbations. We examined microbial responses in three layers of a clay-loam loess (topsoil, 0–20 cm; midsoil, 40–60 cm; subsoil, 80–100 cm) to substrate additions (0.8 g glucose-C kg−1 soil) under two temperature regimes (25 and 35°C). Soil C:N ratio was significantly larger in the subsoil (20.3) than topsoil (7.4). Glucose addition significantly increased CO2 efflux during a 30-day incubation period and the relative magnitude of the increase was four times larger in the subsoil than topsoil. The temperature sensitivity (Q10) of soil CO2 efflux increased significantly with soil depth in the absence of glucose addition (i.e., ambient soil), but it decreased under glucose addition. Also, glucose addition significantly increased phenol oxidase and peroxidase activities in the subsoil, which might contribute to the stimulation of microbial CO2 efflux. Composition of the microbial community was more affected by temperature increase in the topsoil, but more responsive to labile C addition in the subsoil. Together, these results indicated that the composition of soil communities and microbial activities in the topsoil and deep soil responded differently to warming and labile C input. Our findings suggest that organic C in deep loess soils can be highly sensitive to environmental changes, emphasizing the need for more long-term monitoring and quantitative assessment of organic C release from this important C pool. Highlights Microbial responses to labile C and warming were examined along a Loess Plateau soil profile. Microbial respiration was more responsive to C addition and warming in deep soil than topsoil. Microbial composition and activity were sensitive to temperature in the topsoil but to labile C in the subsoil. Climate change may facilitate CO2 efflux from deep Loess Plateau soils.}, number={5}, journal={EUROPEAN JOURNAL OF SOIL SCIENCE}, author={Bai, Tongshuo and Tao, Jinjin and Li, Zhen and Shu, Meng and Yan, Xuebin and Wang, Peng and Ye, Chenglong and Guo, Hui and Wang, Yi and Hu, Shuijin}, year={2019}, month={Sep}, pages={1025–1036} }
 @article{xu_wolfe_diez_zheng_guo_hu_2019, title={Differential germination strategies of native and introduced populations of the invasive species Plantago virginica}, ISSN={["1314-2488"]}, DOI={10.3897/neobiota.43.30392}, abstractNote={Germination strategies are critically important for the survival, establishment and spread of plant species. Although many plant traits related to invasiveness have been broadly studied, the earliest part of the life cycle, germination, has received relatively little attention. Here, we compared the germination patterns between native (North America) and introduced (China) populations of Plantagovirginica for four consecutive years to examine whether there has been adaptive differentiation in germination traits and how these traits are related to local climatic conditions. We found that the introduced populations of P.virginica had significantly higher germination percentages and faster and shorter durations of germination than native populations. Critically, the native populations had a significantly larger proportion of seeds that stayed dormant in all four years, with only 60% of seeds germinating in year 1 (compared to >95% in introduced populations). These results demonstrate striking differences in germination strategies between native and introduced populations which may contribute to their successful invasion. Moreover, the germination strategy of P.virginica in their native range exhibited clear geographical variation across populations, with trends towards higher germination percentages at higher latitudes and lower annual mean temperatures and annual precipitation. In the introduced range, however, their germination strategies were more conserved, with less variation amongst populations, suggesting that P.virginica may have experienced strong selection for earlier life history characteristics. Our findings highlight the need to examine the role of rapid evolution of germination traits in facilitating plant invasion.}, number={43}, journal={NEOBIOTA}, author={Xu, Xinyu and Wolfe, Lorne and Diez, Jeffrey and Zheng, Yi and Guo, Hui and Hu, Shuijin}, year={2019}, month={Mar}, pages={101–118} }
 @article{chen_xing_lan_saleem_wu_hu_bai_2019, title={Direct and indirect effects of nitrogen enrichment on soil organisms and carbon and nitrogen mineralization in a semi-arid grassland}, volume={33}, ISSN={["1365-2435"]}, DOI={10.1111/1365-2435.13226}, number={1}, journal={FUNCTIONAL ECOLOGY}, author={Chen, Dima and Xing, Wen and Lan, Zhichun and Saleem, Muhammad and Wu, Yunqiqige and Hu, Shuijin and Bai, Yongfei}, year={2019}, month={Jan}, pages={175–187} }
 @article{sun_guo_guo_guo_hu_2019, title={Divergent responses of leaf N:P:K stoichiometry to nitrogen fertilization in rice and weeds}, volume={67}, ISSN={["1550-2759"]}, DOI={10.1017/wsc.2019.7}, abstractNote={Abstract Nitrogen (N) inputs have been found to exert strong influence on leaf stoichiometry in natural ecosystems, but there are few studies investigating the effects of N in agroecosystems. Using a 5-yr fertilization experiment in rice fields, we examined the effects of N inputs on leaf stoichiometry of one crop, rice ( Oryza sativa L.), and its four common weeds, barnyardgrass [ Echinochloa crus-galli (L.) P. Beauv.], Monochoria korsakowii Regel and Mack, alligatorweed [ Alternanthera philoxeroides (Mart.) Griseb.], and Japanese mazus [ Mazus pumilus (Burm. f.) Steenis], and further evaluated whether and how straw return mediates these effects. We found that rice and weed leaf nitrogen:phosphorus:potassium (N:P:K) stoichiometry exhibited divergent responses to N fertilizer. Weed leaf N:P:K stoichiometry was not sensitive to low (120 kg N ha −1 ) and regular (240 kg N ha −1 ) N inputs, but rice plants were, with significantly increased leaf N concentration and N:P and N:K ratios. The opposite trend was found for high N inputs (360 kg N ha −1 ). Rice leaf N concentration [N] did not increase further, and N:P ratios even decreased, whereas E. crus-galli and M. korsakowii had significantly increased [N] and N-related stoichiometry. We also found that the positive effects of regular N inputs on rice leaf N:P and N:K ratios were significantly dampened by straw return, but the positive effects on N:P ratios in M. pumilus leaves were enhanced by straw return. Compared with weeds, rice leaves contained low elemental concentrations across fertilization levels at grain-filling stages. These results indicate that rice has a lower N requirement than weeds at grain-filling stages, and the N supply should be managed at a relative low level to reduce the nutrient acquisition and competitive abilities of weeds. From a stoichiometric perspective, this study highlights the importance of N management in combination with straw return in controlling weeds and increasing the nutrient-use efficiency of crops.}, number={3}, journal={WEED SCIENCE}, author={Sun, Xiao and Guo, Jiuxin and Guo, Shiwei and Guo, Hui and Hu, Shuijin}, year={2019}, month={May}, pages={339–345} }
 @article{chen_saleem_cheng_mi_chu_tuvshintogtokh_hu_bai_2019, title={Effects of aridity on soil microbial communities and functions across soil depths on the Mongolian Plateau}, volume={33}, ISSN={["1365-2435"]}, DOI={10.1111/1365-2435.13359}, abstractNote={Arid and semi-arid grassland ecosystems cover about 15% of the global land surface and provide vital soil carbon (C) and nitrogen (N) sequestration. Although half of the soil C and N is stored in deep soils (below 30 cm), no regional-scale study of microbial properties and their functions through the soil profile has been conducted in these drylands. To explore the distribution and determinants of microbial properties and C and N mineralization rates through soil profile along aridity gradient at a regional scale, we investigated these variables for four soil layers (0–20, 20–40, 40–60 and 60–100 cm) in 132 plots on the Mongolia Plateau. Soil microbial properties (biomass and bacteria:fungi ratio) and C and N mineralization rates decreased with increasing soil depth and aridity at the regional scale. Aridity-induced declines in soil microbial properties mainly resulted from the negative effects of aridity on ANPP/root biomass and soil organic C (SOC) in the surface soil layers (0–20 and 20–40 cm) but from the direct and indirect (via SOC and soil C/N) negative effects of aridity in the deep soil layers (40–60 and 60–100 cm). Aridity-induced declines in soil C mineralization rates mainly resulted from the negative indirect effect of aridity on SOC and microbial properties in each soil layer, with weaker effects of SOC and stronger effects of soil microbes in the deep soil layers. Aridity-induced declines in soil N mineralization rates mainly resulted from the negative indirect effect of aridity on SOC in the three soil layers above 60 cm and mainly resulted from the negative direct effect of aridity in the 60–100 cm soil layer. Aridity via direct or indirect effects strongly determined the patterns of soil microbial properties and C and N mineralization throughout soil profiles on the Mongolian Plateau. These findings suggest that the increases in aridity are likely to induce changes in soil micro-organisms and their associated functions across soil depths of semi-arid grasslands, and future models should consider the dynamic interactions between substrates and microbial properties across soil depths in global drylands. A plain language summary is available for this article.}, number={8}, journal={FUNCTIONAL ECOLOGY}, author={Chen, Dima and Saleem, Muhammad and Cheng, Junhui and Mi, Jia and Chu, Pengfei and Tuvshintogtokh, Indree and Hu, Shuijin and Bai, Yongfei}, year={2019}, month={Aug}, pages={1561–1571} }
 @article{shu_zhao_li_zhang_wang_hu_2019, title={Effects of global change factors and living roots on root litter decomposition in a Qinghai-Tibet alpine meadow}, volume={9}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-019-53450-5}, abstractNote={Abstract Roots account for a major part of plant biomass in Tibetan alpine meadows. Understanding root decomposition with global change is key to predict carbon (C) and nutrient dynamics on the Qinghai-Tibet Plateau. Yet, few experiments have carefully examined root decomposition as influenced by global change. We conducted a field study to investigate the effects of nitrogen (N) addition, air warming, precipitation change, and the presence/absence of living roots on root decomposition in a Tibetan alpine meadow. Our results showed that N addition increased the mass and C remaining, and induced N accumulation in the litter. Increased precipitation significantly amplified the positive effect of N addition on litter mass remaining. The presence of alive roots in the litterbags decreased root litter C remaining but significantly increased N and phosphorus remaining of the litter. However, we did not find any significant effects of air warming on the litter decomposition. In the Qinghai-Tibet Plateau, N deposition is predicted to increase and precipitation regime is predicted to change. Our results suggest that the interaction between increased N and precipitation may reduce root decomposition in the Qinghai-Tibet Plateau in the future, and that the large stock of living roots exert a dominant impact on nutrient dynamics of root decomposition in the Tibetan alpine systems.}, journal={SCIENTIFIC REPORTS}, author={Shu, Meng and Zhao, Qingzhou and Li, Zhen and Zhang, Lin and Wang, Peng and Hu, Shuijin}, year={2019}, month={Nov} }
 @article{chen_zhang_tang_su_tian_zhang_li_hu_2019, title={Enhanced Pb immobilization via the combination of biochar and phosphate solubilizing bacteria}, volume={127}, ISSN={["1873-6750"]}, DOI={10.1016/j.envint.2019.03.068}, abstractNote={Application of biochar in heavy metal remediation suffers from lack of long-term stability. Phosphate-solubilizing bacteria (PSB) are able to elevate P release and the subsequent reaction with Pb to form stable pyromorphite. This study investigated the feasibility of applying PSB modified biochar to enhance immobilization of Pb2+. An alkaline biochar produced from rice husk (RB) and a slightly acidic biochar produced from sludge (SB) were selected. It showed that the biochars can effectively remove Pb2+ via adsorption, i.e., aqueous Pb concentrations after RB and SB addition were reduced by 18.61 and 53.89% respectively. The addition of PSB increased the Pb2+ removal for both biochars (to 24.11 and 60.85%, respectively). In particular, PSB significantly enhanced the formation of stable pyromorphite on surface of SB. This is due to that the evenly distributed PSB enhanced P release and regulated pH on the biochar surface. Moreover, small particles (<0.074 mm) showed their higher ability to induce the formation of pyromorphite, for both RB and SB. Nevertheless, SB demonstrated higher capability of sorption, together with its more abundant P content, which provided a more suitable platform to attract PSB to immobilize heavy metals. Therefore, the combination of biochar and PSB is a promising candidate material for heavy metal remediation. However, the types and particle size distribution of biochar should be addressed.}, journal={ENVIRONMENT INTERNATIONAL}, author={Chen, Haoming and Zhang, Jiawen and Tang, Lingyi and Su, Mu and Tian, Da and Zhang, Lin and Li, Zhen and Hu, Shuijin}, year={2019}, month={Jun}, pages={395–401} }
 @article{yang_niu_collins_yan_ji_ling_zhou_du_guo_hu_2019, title={Grazing practices affect the soil microbial community composition in a Tibetan alpine meadow}, volume={30}, ISSN={["1099-145X"]}, DOI={10.1002/ldr.3189}, abstractNote={Grazing is the primary land‐use activity on the Tibetan Plateau and can affect soil microbes and their function through aboveground vegetation removal, animal trampling, and manure deposition. Two distinct grazing systems (i.e., winter grazing [WG] and annual grazing [AG]) dominate on the Tibetan Plateau, but their effects on soil microbes have rarely been assessed. Taking advantage of a 5‐year field experiment that controlled timing and density of grazers via fence exclosures, we examined impacts of different grazing practices on the biomass, diversity, and composition of the soil microbial community in a Tibetan alpine meadow. On the basis of high‐throughput sequencing, we found that grazing had no significant effects on bacterial and fungal α‐diversities but altered their community compositions. Although total soil carbon (TC), total soil nitrogen (TN), and carbon/nitrogen (C/N) were related to both bacterial and fungal community compositions, plant shoot biomass only correlated with bacteria, and soil pH and moisture significantly influenced fungi under grazing. Also, grazing altered plant community composition but did not lead to corresponding changes in bacterial or fungal community composition. Moreover, grazing practices affected the relative abundance of specific bacterial and fungal taxa, reducing Actinobacteria but increasing Basidiomycete fungi in WG. Soil TC and TN were higher, and the soil microbial community was more stable in AG than WG, likely due to more stable litter inputs in AG. Together, these results showed that AG was less disruptive to soil microbes, suggesting that AG may provide a viable option for sustainable utilization and conservation of these fragile alpine systems.}, number={1}, journal={LAND DEGRADATION & DEVELOPMENT}, author={Yang, Fei and Niu, Kechang and Collins, Courtney G. and Yan, Xuebin and Ji, Yangguang and Ling, Ning and Zhou, Xianhui and Du, Guozhen and Guo, Hui and Hu, Shuijin}, year={2019}, month={Jan}, pages={49–59} }
 @article{zhang_hu_han_wu_tian_su_wang_li_hu_2019, title={Influences of multiple clay minerals on the phosphorus transport driven by Aspergillus niger}, volume={177}, ISSN={["1872-9053"]}, DOI={10.1016/j.clay.2019.04.026}, abstractNote={Phosphorus (P) is a major limiting nutrient for plant growth. Clay minerals are able to work as active centers in soil system due to their high surface area and CEC. Yet, effects of clay minerals on P biogeochemical cycle driven by microorganisms are still unclear. In this study, hydroxylapatite and three typical clay minerals (kaolinite, palygorskite, and montmorillonite) were incubated with Aspergillus niger to investigate microbial influences on P release and adsorption. Due to the mineral particles, hyphae wrapped small montmorillonite particles (<10 μm, confirmed by SEM and TEM), which promoted microbial bioactivities, e.g., respiration and acid production. P consumption by the fungus lowered the available P from 143 to 68 ppm. Meanwhile, ATR-IR spectra and HPLC analysis confirmed the intense adsorption of oxalic acid (the primary microbial secretion) onto montmorillonite. Despite the higher acid production, both the high adsorption capability of the clay and the acid consumed by phosphate dissolution caused that pH values increased from ~2 to ~4 after montmorillonite addition. In contrast, low CEC, dispersibility, and surface area of kaolinite and palygorskite limited their ability to enhance microbial activities and the subsequent interactions with hyphae. Therefore, clay minerals, especially montmorillonite, can drive P transport with the favor from fungi in ecosystem.}, journal={APPLIED CLAY SCIENCE}, author={Zhang, Lin and Hu, Yunxiao and Han, Feiyu and Wu, Yiling and Tian, Da and Su, Mu and Wang, Shimei and Li, Zhen and Hu, Shuijin}, year={2019}, month={Sep}, pages={12–18} }
 @misc{zhang_li_wu_hu_2019, title={Invasive plants differentially affect soil biota through litter and rhizosphere pathways: a meta-analysis}, volume={22}, ISSN={["1461-0248"]}, DOI={10.1111/ele.13181}, abstractNote={Invasive plants affect soil biota through litter and rhizosphere inputs, but the direction and magnitude of these effects are variable. We conducted a meta-analysis to examine the different effects of litter and rhizosphere of invasive plants on soil communities and nutrient cycling. Our results showed that invasive plants increased bacterial biomass by 16%, detritivore abundance by 119% and microbivore abundance by 89% through litter pathway. In the rhizosphere, invasive plants reduced bacterial biomass by 12%, herbivore abundance by 55% and predator abundance by 52%, but increased AM fungal biomass by 36%. Moreover, CO2 efflux, N mineralisation rate and enzyme activities were all higher in invasive than native rhizosphere soils. These findings indicate that invasive plants may support more decomposers that in turn stimulate nutrient release via litter effect, and enhance nutrient uptake by reducing root grazing but forming more symbioses in the rhizosphere. Thus, we hypothesise that litter- and root-based loops are probably linked to generate positive feedback of invaders on soil systems through stimulating nutrient cycling, consequently facilitating plant invasion. Our findings from limited cases with diverse contexts suggest that more studies are needed to differentiate litter and rhizosphere effects within single systems to better understand invasive plant-soil interactions.}, number={1}, journal={ECOLOGY LETTERS}, author={Zhang, Pei and Li, Bo and Wu, Jihua and Hu, Shuijin}, year={2019}, month={Jan}, pages={200–210} }
 @article{jiang_qian_wang_feng_huang_hungate_kessel_horwath_zhang_qin_et al._2019, title={Limited potential of harvest index improvement to reduce methane emissions from rice paddies}, volume={25}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.14529}, abstractNote={Rice is a staple food for nearly half of the world's population, but rice paddies constitute a major source of anthropogenic CH4 emissions. Root exudates from growing rice plants are an important substrate for methane-producing microorganisms. Therefore, breeding efforts optimizing rice plant photosynthate allocation to grains, i.e., increasing harvest index (HI), are widely expected to reduce CH4 emissions with higher yield. Here we show, by combining a series of experiments, meta-analyses and an expert survey, that the potential of CH4 mitigation from rice paddies through HI improvement is in fact small. Whereas HI improvement reduced CH4 emissions under continuously flooded (CF) irrigation, it did not affect CH4 emissions in systems with intermittent irrigation (II). We estimate that future plant breeding efforts aimed at HI improvement to the theoretical maximum value will reduce CH4 emissions in CF systems by 4.4%. However, CF systems currently make up only a small fraction of the total rice growing area (i.e., 27% of the Chinese rice paddy area). Thus, to achieve substantial CH4 mitigation from rice agriculture, alternative plant breeding strategies may be needed, along with alternative management.}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Jiang, Yu and Qian, Haoyu and Wang, Ling and Feng, Jinfei and Huang, Shan and Hungate, Bruce A. and Kessel, Chris and Horwath, William R. and Zhang, Xingyue and Qin, Xiaobo and et al.}, year={2019}, month={Feb}, pages={686–698} }
 @article{guo_tian_wang_han_su_wu_li_hu_2019, title={Reduction of Pb availability during surficial leaching in different types of soils with addition of apatite and oxalic acid}, volume={19}, ISSN={["1614-7480"]}, DOI={10.1007/s11368-018-2100-6}, number={2}, journal={JOURNAL OF SOILS AND SEDIMENTS}, author={Guo, Chenmeng and Tian, Weitao and Wang, Zhijun and Han, Feiyu and Su, Mu and Wu, Yiling and Li, Zhen and Hu, Shuijin}, year={2019}, month={Feb}, pages={741–749} }
 @article{su_wei_wang_guo_zhang_wang_guo_hu_2019, title={Sensitivity of plant species to warming and altered precipitation dominates the community productivity in a semiarid grassland on the Loess Plateau}, volume={9}, ISSN={["2045-7758"]}, DOI={10.1002/ece3.5312}, abstractNote={Global warming and changes in precipitation patterns can critically influence the structure and productivity of terrestrial ecosystems. However, the underlying mechanisms are not fully understood. We conducted two independent but complementary experiments (one with warming and precipitation manipulation (+ or – 30%) and another with selective plant removal) in a semiarid grassland on the Loess Plateau, northwestern China, to assess how warming and altered precipitation affect plant community. Our results showed that warming and altered precipitation affected community aboveground net primary productivity (ANPP) through impacting soil moisture. Results of the removal experiment showed competitive relationships among dominant grasses, the dominant subshrub and nondominant species, which played a more important role than soil moisture in the response of plant community to warming and altered precipitation. Precipitation addition intensified the competition but primarily benefited the dominant subshrub. Warming and precipitation reduction enhanced water stresses but increased ANPP of the dominant subshrub and grasses, indicating that plant tolerance to drought critically meditated the community responses. These findings suggest that specie competitivity for water resources as well as tolerance to environmental stresses may dominate the responses of plant communities on the Loess Plateaus to future climate change factors.}, number={13}, journal={ECOLOGY AND EVOLUTION}, author={Su, Fanglong and Wei, Yanan and Wang, Fuwei and Guo, Jiuxin and Zhang, Juanjuan and Wang, Yi and Guo, Hui and Hu, Shuijin}, year={2019}, month={Jul}, pages={7628–7638} }
 @article{chen_zhang_cao_fu_hu_wu_zhao_liu_2019, title={Stand age and species traits alter the effects of understory removal on litter decomposition and nutrient dynamics in subtropical Eucalyptus plantations}, volume={20}, ISBN={2351-9894}, DOI={10.1016/j.gecco.2019.e00693}, abstractNote={Litter decomposition is a crucial ecological process that regulates nutrient cycling. However, the effects of understory plants and overstory trees on litter decomposition and nutrient dynamics are still poorly understood. We conducted understory plants removal and/or overstory trees removal to examine the resulting effects on litter decomposition and nutrient mineralization in two Eucalyptus plantations with contrasting ages (8-yr-old, 29-yr-old) in subtropical China. Litter bags containing naturally senesced leaves of either overstory Eucalyptus urophylla or understory Dicranopteris dichotoma were placed in field and periodically collected for analyses of carbon (C), nitrogen (N), phosphorus (P) and calculation of mass loss. Our results showed that understory plants removal significantly reduced litter decomposition of E. urophylla in both plantations, but N and P mineralization were reduced only in the 8-yr-old plantation. In contrast, it reduced litter decomposition of D. dichotoma only in the 29-yr-old plantation, but had no effects on N and P mineralization in either plantation. In comparison, overstory tree removal did not have any effects on decomposition or mineralization of N and P of E. urophylla and D. dichotoma litters. These results indicate that the role of understory plants in mediating litter decomposition and nutrient mineralization is more important than overstory trees, and it can be altered by stand age and plant species. Our findings could facilitate the understanding of ecological processes of litter decomposition and nutrient mineralization in subtropical forest ecosystems.}, journal={GLOBAL ECOLOGY AND CONSERVATION}, author={Chen, Yuanqi and Zhang, Yanju and Cao, Jianbo and Fu, Shenglei and Hu, Shuijin and Wu, Jianping and Zhao, Jie and Liu, Zhanfeng}, year={2019}, month={Oct} }
 @article{luo_xu_zheng_guo_hu_2019, title={The role of phenotypic plasticity and rapid adaptation in determining invasion success of Plantago virginica}, volume={21}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-019-02004-x}, number={8}, journal={BIOLOGICAL INVASIONS}, author={Luo, Xi and Xu, Xinyu and Zheng, Yi and Guo, Hui and Hu, Shuijin}, year={2019}, month={Aug}, pages={2679–2692} }
 @article{yang_ma_rong_zeng_wang_hu_ye_zheng_2019, title={Wheat Straw Return Influences Nitrogen-Cycling and Pathogen Associated Soil Microbiota in a Wheat-Soybean Rotation System}, volume={10}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2019.01811}, abstractNote={Returning straw to soil is an effective way to sustain or improve soil quality and crop yields. However, a robust understanding of the impact of straw return on the composition of the soil microbial communities under field conditions has remained elusive. In this study, we characterized the effects of wheat straw return on soil bacterial and fungal communities in a wheat-soybean rotation system over a 3-year period, using Illumina-based 16S rRNA, and internal transcribed region (ITS) amplicon sequencing. Wheat straw return significantly affected the α-diversity of the soil bacterial, but not fungal, community. It enhanced the relative abundance of the bacterial phylum Proteobacteria and the fungal phylum Zygomycota, but reduced that of the bacterial phylum Acidobacteria, and the fungal phylum Ascomycota. Notably, it enriched the relative abundance of nitrogen-cycling bacterial genera such as Bradyrhizobium and Rhizobium. Preliminary analysis of soil chemical properties indicated that straw return soils had significantly higher total nitrogen (TN) contents than no straw return soils. In addition, the relative abundance of fungal genera containing pathogens was significantly lower in straw return soils relative to control soils, such as Fusarium, Alternaria, and Myrothecium. These results suggested a selection effect from the 3-year continuous straw return treatment and the soil bacterial and fungal communities were moderately changed.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Yang, Hongjun and Ma, Jiaxin and Rong, Zhenyang and Zeng, Dandan and Wang, Yuanchao and Hu, Shuijin and Ye, Wenwu and Zheng, Xiaobo}, year={2019}, month={Aug} }
 @article{tian_lai_zou_guo_tang_su_li_hu_2018, title={A contrast of lead immobilization via bioapatite under elevated CO2 between acidic and alkaline soils}, volume={34}, ISSN={["1475-2743"]}, DOI={10.1111/sum.12448}, abstractNote={Abstract The feasibility of Pb immobilization via bioapatite ( BA p) and CO 2 in the acidic red soil ( RS ) and saline‐alkaline soil ( SS ) was compared in this study. The elevated CO 2 (10% in air) significantly promoted the dissolution of BA p in water, that is, the concentrations of released P were enhanced from 2 to 20 ppm as pH decreased from 6.9 to 5.6. Then, it was shown that 30–40% TCLP leached Pb was removed from RS and SS , with the combination of BA p addition and CO 2 elevation. In RS , the addition of BA p (even without CO 2 ) could significantly increase water‐soluble P. Moreover, some Pb cations were adsorbed onto iron (hydr)oxides within RS . In contrast, CO 2 elevation is essential for enhancing P release in SS as it dramatically increased the dissolution of phosphates. The released P then reacted with Pb cations to form insoluble pyromorphite. Therefore, this combination is effective for Pb immobilization in saline‐alkaline soil whereas adding solely BA p is feasible for acid soil.}, number={4}, journal={SOIL USE AND MANAGEMENT}, author={Tian, D. and Lai, Z. and Zou, X. and Guo, C. and Tang, L. and Su, M. and Li, Z. and Hu, S.}, year={2018}, month={Dec}, pages={542–544} }
 @article{yang_schroeder-moreno_giri_hu_2018, title={Arbuscular Mycorrhizal Fungi and Their Responses to Nutrient Enrichment}, volume={52}, ISBN={["978-3-319-75909-8"]}, ISSN={["1613-3382"]}, DOI={10.1007/978-3-319-75910-4_17}, abstractNote={The roots of most land plants form mycorrhizal associations with soil fungi, in which plants trade carbon for increased nutrient acquisition (e.g., N and P) under nutrient deficiency conditions. However, how nutrient enrichment affects mycorrhiza is still not well understood, in particular under future global changing scenarios such as nitrogen deposition. In this chapter, we first review the major pathways of mycorrhizal-mediated nutrient acquisition and molecular mechanisms of sensing nutrient availability for mycorrhizal fungi and roots. Next, we propose two conceptual models that may control plant C allocation to mycorrhizal fungi in response to nutrient enrichment: reciprocal reward model and root-mycorrhiza trade-off model. We also describe a plant-centric model and fungal-centric model to explain responses of the mycorrhizal fungal community to nutrient enrichment as well as examine impacts of nutrient inputs on mycorrhizas functioning.}, journal={ROOT BIOLOGY}, author={Yang, Haishui and Schroeder-Moreno, Michelle and Giri, Bhoopander and Hu, Shuijin}, year={2018}, pages={429–449} }
 @article{zhang_qiu_cheng_wang_liu_tu_bowman_burkey_bian_zhang_et al._2018, title={Atmospheric CO2 Enrichment and Reactive Nitrogen Inputs Interactively Stimulate Soil Cation Losses and Acidification}, volume={52}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.8b00495}, abstractNote={Reactive N inputs (Nr) may alleviate N-limitation of plant growth and are assumed to help sustain plant responses to the rising atmospheric CO2 (eCO2). However, Nr and eCO2 may elicit a cascade reaction that alters soil chemistry and nutrient availability, shifting the limiting factors of plant growth, particularly in acidic tropical and subtropical croplands with low organic matter and low nutrient cations. Yet, few have so far examined the interactive effects of Nr and eCO2 on the dynamics of soil cation nutrients and soil acidity. We investigated the cation dynamics in the plant–soil system with exposure to eCO2 and different N sources in a subtropical, acidic agricultural soil. eCO2 and Nr, alone and interactively, increased Ca2+ and Mg2+ in soil solutions or leachates in aerobic agroecosystems. eCO2 significantly reduced soil pH, and NH4+-N inputs amplified this effect, suggesting that eCO2-induced plant preference of NH4+-N and plant growth may facilitate soil acidification. This is, to our knowledge, the first direct demonstration of eCO2 enhancement of soil acidity, although other studies have previously shown that eCO2 can increase cation release into soil solutions. Together, these findings provide new insights into the dynamics of cation nutrients and soil acidity under future climatic scenarios, highlighting the urgency for more studies on plant–soil responses to climate change in acidic tropical and subtropical ecosystems.}, number={12}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Zhang, Li and Qiu, Yunpeng and Cheng, Lei and Wang, Yi and Liu, Lingli and Tu, Cong and Bowman, Dan C. and Burkey, Kent O. and Bian, Xinmin and Zhang, Weijian and et al.}, year={2018}, month={Jun}, pages={6895–6902} }
 @article{fang_yu_liu_hu_chapin_2018, title={Climate change, human impacts, and carbon sequestration in China INTRODUCTION}, volume={115}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.1700304115}, abstractNote={The scale of economic growth in China during the past three decades is unprecedented in modern human history. China is now the world’s second largest economic entity, next to the United States. However, this fast economic growth puts China’s environment under increasing stresses. China can be viewed as a massive “laboratory” with complex interactions between socioeconomic and natural systems, providing an excellent opportunity to examine how environmental changes and intensive human economic activities influence natural systems. This special feature explores the impacts of climate change and human activities on the structure and functioning of ecosystems, with emphasis on quantifying the magnitude and distribution of carbon (C) pools and C sequestration in China’s terrestrial ecosystems. We also document how species diversity, species traits, and nitrogen (N) and phosphorus (P) stoichiometry mediate ecosystem C pool and vegetation production. This overview paper introduces the background and scientific significance of the research project, presents the underlying conceptual framework, and summarizes the major findings of each paper.

Reducing CO2 emissions to mitigate regional and global climate change is one of the most challenging issues facing humanity (1). At present, China has the largest annual CO2 emissions in the world ( Upper graph in Fig. 1), placing it in the spotlight of efforts to manage global C emissions and design climate-change policy. It is therefore critical to improve our understanding of the C budget and its dynamics in China to mitigate climate change at both regional and global scales.



Fig. 1. 
Evolution in total national GDP, population, and fossil fuel CO2 emissions, together with trajectory of the national policies in China between 1945 and 2015. ( Upper ) GDP, population, and CO2 emissions. The CO2 emissions data were from Oak Ridge National Laboratory (cdiac.ess-dive.lbl.gov/), and population and GDP data from the World Bank (https://data.worldbank.org/country/). ( Lower ) National … 



[↵][1]1To whom correspondence may be addressed. Email: jyfang{at}urban.pku.edu.cn, fangjingyun{at}ibcas.ac.cn, or terry.chapin{at}alaska.edu.

 [1]: #xref-corresp-1-1}, number={16}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Fang, Jingyun and Yu, Guirui and Liu, Lingli and Hu, Shuijin and Chapin, F. Stuart, III}, year={2018}, month={Apr}, pages={4015–4020} }
 @article{yue_fei-yue_xing-jun_shui-jin_xin_jian-fei_2018, title={Components Analysis of Biochar Based on Near Infrared Spectroscopy Technology}, volume={46}, ISSN={["1872-2040"]}, DOI={10.1016/s1872-2040(17)61081-8}, abstractNote={This study aims to establish a rapid quantitative analysis method for biochar based on near infrared spectroscopy (NIRS) technology. Near infrared spectra of 163 samples in the 10000–3800 cm–1 (1000–2632 nm) range were collected, and the contents of fixed carbon (FC), volatile matter (VM) and ash of samples were also analyzed. A partial least square (PLS) model for FC, VM and Ash was established after the model spectral ranges were optimized, the optimal factors were determined, and the raw spectra were pretreated by multiple scatter correction and second derivative (MSC + SD) method. Finally, the prediction performance of predictive model was evaluated. The results showed that the PLS model had a good prediction ability, and the predicted coefficient R2p of actual values vs prediction values for FC, VM and ash were 0.9423, 0.9517 and 0.9265, respectively. Root mean square error of prediction (RMSEP) was 0.1074, 0.1201 and 0.1243, and ratios of prediction to deviation (RPD) were 3.51, 4.28 and 2.03, respectively. The PLS model had good accuracy and precision for both of FC and VM, and could be used as a quantitative method for FC and VM contents analysis. Nevertheless, PLS model need to improve the precision for Ash analysis according to RPD value. This method provides a fast and effective technical means for the quantitative analysis of biochar components.}, number={4}, journal={CHINESE JOURNAL OF ANALYTICAL CHEMISTRY}, author={Yue, Xie and Fei-Yue, Li and Xing-Jun, Fan and Shui-Jin, Hu and Xin, Xiao and Jian-Fei, Wang}, year={2018}, month={Apr}, pages={609–615} }
 @article{qu_jiang_guo_burkey_zobel_shew_hu_2018, title={Contrasting Warming and Ozone Effects on Denitrifiers Dominate Soil N2O Emissions}, volume={52}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.8b01093}, abstractNote={Nitrous oxide (N2O) in the atmosphere is a major greenhouse gas and reacts with volatile organic compounds to create ozone (an air pollutant) in the troposphere. Climate change factors such as warming and elevated ozone (eO3) affect N2O fluxes, but the direction and magnitude of these effects are uncertain and the underlying mechanisms remain unclear. We examined the impact of simulated warming (control + 3.6 °C) and eO3 (control + 45 ppb) on soil N2O fluxes in a soybean agroecosystem. Results obtained showed that warming significantly increased soil labile C, microbial biomass, and soil N mineralization, but eO3 reduced these parameters. Warming enhanced N2O-producing denitrifers (nirS- and nirK-type), corresponding to increases in both the rate and sum of N2O emissions. In contrast, eO3 significantly reduced both N2O-producing and N2O-consuming (nosZ-type) denitrifiers but had no impact on N2O emissions. Further, eO3 offsets the effects of warming on soil labile C, microbial biomass, and the population size of denitrifiers but still increased N2O emissions, indicating a direct effect of temperature on N2O emissions. Together, these findings suggest that warming may promote N2O production through increasing both the abundance and activities of N2O-producing microbes, positively feeding back to the ongoing climate change.}, number={19}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Qu, Yunpeng and Jiang, Yu and Guo, Lijin and Burkey, Kent O. and Zobel, Richard W. and Shew, H. David and Hu, Shuijin}, year={2018}, month={Oct}, pages={10956–10966} }
 @article{li_deng_chen_yang_zheng_dai_zhang_wang_hu_2018, title={Contrasting physical and biochemical properties of orchard soils suppressive and conducive to Fusarium wilt of banana}, volume={34}, ISSN={["1475-2743"]}, DOI={10.1111/sum.12390}, abstractNote={Fusarium wilt disease is one of the most serious soil-borne diseases in banana orchards worldwide. Some soils are suppressive to Fusarium wilt, although the mechanisms are still unclear. In this study, two typical banana-growing soils (ultisol and inceptisol), which were either suppressive or conducive to Fusarium wilt, were collected from Hainan, China. Particle size distribution, pH values, electrical conductivity (EC), enzyme activities and microbial polymerase chain reaction amplification of the soil samples were analysed. The suppressive soils had significantly more >2 and <0.053 mm aggregates than the conducive soils. In addition, the suppressive soils had a comparatively even size distribution within the range of 0–0.25 mm. Total carbon, total nitrogen and soil enzyme activities in the aggregates of suppressive soils were also significantly higher than those in the conducive soils. For example, soil invertase activities in the >2 mm aggregates were 7.9–11.9 and 3.2–3.3 mg/g for the suppressive and conducive soils, respectively. Furthermore, in situ EC can be applied as an indicator of the integrated contrast between the suppressive and conducive soils, and could be a new tool for monitoring soil-borne disease.}, number={1}, journal={SOIL USE AND MANAGEMENT}, author={Li, Z. and Deng, Z. and Chen, S. and Yang, H. and Zheng, Y. and Dai, L. and Zhang, F. and Wang, S. and Hu, Shuijin}, year={2018}, month={Mar}, pages={154–162} }
 @article{zhao_wang_hu_zhang_ouyang_zhang_huang_zhao_wu_xie_et al._2018, title={Economics- and policy-driven organic carbon input enhancement dominates soil organic carbon accumulation in Chinese croplands}, volume={115}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.1700292114}, abstractNote={Significance Soil organic carbon (C) stock in Chinese croplands increased by about 140 kg C ha −1 year −1 from 1980 to 2011. This soil organic C sequestration was largely due to drastic changes in management practices, such as fertilization, tillage, and residue treatments, induced by economic and policy incentives. Our analysis also indicates that excessive N inputs and inability to incorporate residue C into deeper soils will likely constrain the future C sequestration in Chinese croplands. These findings provide new insights into the causes and limitations of economics- and policy-driven soil C sequestration in China and offer some guidance for soil C management in many developing countries that are going through the similar economic and social transformations.}, number={16}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Zhao, Yongcun and Wang, Meiyan and Hu, Shuijin and Zhang, Xudong and Ouyang, Zhu and Zhang, Ganlin and Huang, Biao and Zhao, Shiwei and Wu, Jinshui and Xie, Deti and et al.}, year={2018}, month={Apr}, pages={4045–4050} }
 @article{williams_wells_dickey_hu_maul_raskin_reberg-horton_mirsky_2018, title={Establishing the relationship of soil nitrogen immobilization to cereal rye residues in a mulched system}, volume={426}, ISSN={["1573-5036"]}, DOI={10.1007/s11104-018-3566-0}, abstractNote={Soil nitrogen (N) immobilization from cover crop residues may help suppress weeds. We established a gradient of cereal rye shoot biomass to determine the extent that soil N can be immobilized and its effect on redroot pigweed (Amaranthus retroflexus L.). A microplot study was conducted in no-till cereal rye (Secale cereale L.)—soybean (Glycine max L. (Merr.)) systems at two sites in eastern USA. Microplots received 0, 2000, 5000, 8000, 12,000 or 15,000 kg ha−1 of cereal rye shoot biomass, and were injected with two mg 15N kg−1 soil 5 cm below the soil surface. Pigweeds were sown and allowed to germinate. Maximum rates of cereal rye shoot decomposition were observed at ≥5000 kg ha−1. Although cereal rye shoot N declined, shoots became enriched with 15N, indicating fungal transfer of soil N to shoots. Soil inorganic N declined by an average of 5 kg N ha−1. Pigweed tissue N and biomass were reduced in the presence of cereal rye. The magnitude of pigweed N reduction was similar across all shoot application rates. We found weak evidence for a cereal rye shoot-based N immobilization mechanism of weed suppression. Our results indicate N immobilization may be primarily due to root residues.}, number={1-2}, journal={PLANT AND SOIL}, author={Williams, Alwyn and Wells, M. Scott and Dickey, David A. and Hu, Shuijin and Maul, Jude and Raskin, Daniel T. and Reberg-Horton, S. Chris and Mirsky, Steven B.}, year={2018}, month={May}, pages={95–107} }
 @article{ren_taube_stein_zhang_bai_hu_2018, title={Grazing weakens temporal stabilizing effects of diversity in the Eurasian steppe}, volume={8}, ISSN={["2045-7758"]}, DOI={10.1002/ece3.3669}, abstractNote={Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity-stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups (PFGs) composition and species asynchrony, which are closely correlated with ecosystem stability, remain unclear. We conducted a six-year grazing experiment in a semi-arid steppe, using seven levels of grazing intensity (0, 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 sheep per hectare) and two grazing systems (i.e., a traditional, continuous grazing system during the growing period (TGS), and a mixed one rotating grazing and mowing annually (MGS)), to examine the effects of grazing system and grazing intensity on the abundance and composition of PFGs and diversity-stability relationships. Ecosystem stability was similar between mixed and continuous grazing treatments. However, within the two grazing systems, stability was maintained through different pathways, that is, along with grazing intensity, persistence biomass variations in MGS, and compensatory interactions of PFGs in their biomass variations in TGS. Ecosystem temporal stability was not decreased by species loss but rather remain unchanged by the strong compensatory effects between PFGs, or a higher grazing-induced decrease in species asynchrony at higher diversity, and a higher grazing-induced increase in the temporal variation of productivity in diverse communities. Ecosystem stability of aboveground net primary production was not related to species richness in both grazing systems. High grazing intensity weakened the temporal stabilizing effects of diversity in this semi-arid grassland. Our results demonstrate that the productivity of dominant PFGs is more important than species richness for maximizing stability in this system. This study distinguishes grazing intensity and grazing system from diversity effects on the temporal stability, highlighting the need to better understand how grazing regulates ecosystem stability, plant diversity, and their synergic relationships.}, number={1}, journal={ECOLOGY AND EVOLUTION}, author={Ren, Haiyan and Taube, Friedhelm and Stein, Claudia and Zhang, Yingjun and Bai, Yongfei and Hu, Shuijin}, year={2018}, month={Jan}, pages={231–241} }
 @article{li_su_duan_tian_yang_guo_wang_hu_2018, title={Induced biotransformation of lead (II) by Enterobacter sp in SO4-PO4-Cl-Para solution}, volume={357}, ISSN={["1873-3336"]}, DOI={10.1016/j.jhazmat.2018.06.032}, abstractNote={Pb is a toxic heavy metal in contaminated soil and water, resulted from industrial activities, mine exploration, etc. Phosphate solubilizing bacteria are able to secrete organic acids and further to enhance the solubility of phosphates. Enterobacter. sp and geological fluorapatite (FAp) were applied to investigate the biotransformation of Pb2+ in solution with SO42-, PO43-, and Cl- species by ICP-OES, ATR-IR, XRD, and SEM. Enterobacter. sp can lower pH of the medium to ∼4. Meanwhile, >90% mobile Pb (declining from 1000 to 30 ppm) was immobilized via the combination of Enterobacter. sp and FAp. With the addition of FAp and Pb, pyromorphite was precipitated, but with relatively low content. In contrast, abundant anglesite mineral was formed in such weakly acidic system. These anglesite crystals can even absorb phosphates particles onto their surface. Additionally, geochemical modeling confirms the formation of anglesite and cerussite under weekly acidic and alkalic condition respectively, especially when H2PO4- concentration <10-8 mM. Furthermore, the presence of Cl- in solution leads to the formation of chloropyromorphite when H2PO4- concentration >10-12 mM, especially under neutral environment. This study explored the biotransformation of Pb in SO4-PO4-Cl aqueous system and hence provided guidance on bioremediation of Pb by bacteria and FAp.}, journal={JOURNAL OF HAZARDOUS MATERIALS}, author={Li, Zhen and Su, Mu and Duan, Xiaofang and Tian, Da and Yang, Mengying and Guo, Jieyun and Wang, Shimei and Hu, Shuijin}, year={2018}, month={Sep}, pages={491–497} }
 @article{tang_duan_kong_zhang_zheng_li_mei_zhao_hu_2018, title={Influences of climate change on area variation of Qinghai Lake on Qinghai-Tibetan Plateau since 1980s}, volume={8}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-018-25683-3}, abstractNote={Abstract Qinghai-Tibetan Plateau is the most sensitive region to global warming on Earth. Qinghai Lake, the largest lake on the plateau, has experienced evident area variation during the past several decades. To quantify the area changes of Qinghai Lake, a satellite-based survey based on Landsat images from the 1980s to 2010s has been performed. In addition, meteorological data from all the seven available stations on Qinghai-Tibetan Plateau has been analyzed. Area of Qinghai Lake shrank ~2% during 1987–2005, and then increased ~3% from 2005–2016. Meanwhile, the average annual temperature increased 0.319 °C/10 y in the past 50 years, where the value is 0.415 °C/10 y from 2005–2016. The structural equation modeling (SEM) shows that precipitation is the primary factor influencing the area of Qinghai Lake. Moreover, temperature might be tightly correlated with precipitation, snow line, and evaporation, thereby indirectly causes alternations of the lake area. This study elucidated the significant area variation of water body on the Qinghai-Tibetan Plateau under global warming since 1980s.}, journal={SCIENTIFIC REPORTS}, author={Tang, Lingyi and Duan, Xiaofang and Kong, Fanjin and Zhang, Fan and Zheng, Yangfan and Li, Zhen and Mei, Yi and Zhao, Yanwen and Hu, Shuijin}, year={2018}, month={May} }
 @article{zhang_wang_yuan_xu_tu_fisk_zhang_chen_ritchie_hu_2018, title={Irrigation and weed control alter soil microbiology and nutrient availability in North Carolina Sandhill peach orchards}, volume={615}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2017.09.265}, abstractNote={Orchard management practices such as weed control and irrigation are primarily aimed at maximizing fruit yields and economic profits. However, the impact of these practices on soil fertility and soil microbiology is often overlooked. We conducted a two-factor experimental manipulation of weed control by herbicide and trickle irrigation in a nutrient-poor peach (Prunus persica L. cv. Contender) orchard near Jackson Springs, North Carolina. After three and eight years of treatments, an array of soil fertility parameters were examined, including soil pH, soil N, P and cation nutrients, microbial biomass and respiration, N mineralization, and presence of arbuscular mycorrhizal fungi (AMF). Three general trends emerged: 1) irrigation significantly increased soil microbial biomass and activity, 2) infection rate of mycorrhizal fungi within roots were significantly higher under irrigation than non-irrigation treatments, but no significant difference in the AMF community composition was detected among treatments, 3) weed control through herbicides reduced soil organic matter, microbial biomass and activity, and mineral nutrients, but had no significant impacts on root mycorrhizal infection and AMF communities. Weed-control treatments directly decreased availability of soil nutrients in year 8, especially soil extractable inorganic N. Weed control also appears to have altered the soil nutrients via changes in soil microbes and altered net N mineralization via changes in soil microbial biomass and activity. These results indicate that long-term weed control using herbicides reduces soil fertility through reducing organic C inputs, nutrient retention and soil microbes. Together, these findings highlight the need for alternative practices such as winter legume cover cropping that maintain and/or enhance organic inputs to sustain the soil fertility.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Zhang, Yi and Wang, Liangju and Yuan, Yongge and Xu, Jing and Tu, Cong and Fisk, Connie and Zhang, Weijian and Chen, Xin and Ritchie, David and Hu, Shuijin}, year={2018}, month={Feb}, pages={517–525} }
 @article{ren_eviner_gui_wilson_cobb_yang_zhang_hu_bai_2018, title={Livestock grazing regulates ecosystem multifunctionality in semi-arid grassland}, volume={32}, ISSN={["1365-2435"]}, DOI={10.1111/1365-2435.13215}, abstractNote={Livestock grazing has been shown to alter the structure and functions of grassland ecosystems. It is well acknowledged that grazing pressure is one of the strongest drivers of ecosystem-level effects of grazing, but few studies have assessed how grazing pressure impacts grassland biodiversity and ecosystem multifunctionality (EMF). Here, we assessed how different metrics of biodiversity (i.e., plants and soil microbes) and EMF responded to seven different grazing treatments based on an 11-year field experiment in semi-arid Inner Mongolian steppe. We found that soil organic carbon, plant-available nitrogen and plant functional diversity all decreased even at low grazing pressure, while above-ground primary production and bacterial abundance decreased only at high levels of grazing pressure. Structural equation models revealed that EMF was driven by direct effects of grazing, rather than the effects of grazing on plant or microbial community composition. Grazing effects on plant functional diversity and soil microbial abundance did have moderate effects on EMF, while plant richness did not. Synthesis. Our results showed ecosystem functions differ in their sensitivity to grazing pressure, requiring a low grazing threshold to achieve multiple goals in the Eurasian steppe. A plain language summary is available for this article.}, number={12}, journal={FUNCTIONAL ECOLOGY}, author={Ren, Haiyan and Eviner, Valerie T. and Gui, Weiyang and Wilson, Gail W. T. and Cobb, Adam B. and Yang, Gaowen and Zhang, Yingjun and Hu, Shuijin and Bai, Yongfei}, year={2018}, month={Dec}, pages={2790–2800} }
 @article{zhang_yan_su_li_wang_wei_ji_yang_zhou_guo_et al._2018, title={Long-term N and P additions alter the scaling of plant nitrogen to phosphorus in a Tibetan alpine meadow}, volume={625}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2017.12.292}, abstractNote={Nitrogen and phosphorus are two important nutrient elements for plants. The current paradigm suggests that the scaling of plant tissue N to P is conserved across environments and plant taxa because these two elements are coupled and coordinately change with each other following a constant allometric trajectory. However, this assumption has not been vigorously examined, particularly in changing N and P environments. We propose that changes in relative availability of N and P in soil alter the N to P relationship in plants. Taking advantage of a 4-yr N and P addition experiment in a Tibetan alpine meadow, we examined changes in plant N and P concentrations of 14 common species. Our results showed that while the scaling of N to P under N additions was similar to the previously reported pattern with a uniform 2/3 slope of the regression between log N and log P, it was significantly different under P additions with a smaller slope. Also, graminoids had different responses from forbs. These results indicate that the relative availability of soil N and P is an important determinant regulating the N and P concentrations in plants. These findings suggest that alterations in the N to P relationships may not only alter plant photosynthate allocation to vegetative or reproductive organs, but also regulate the metabolic and growth rate of plant and promote shifts in plant community composition in a changing nutrient loading environment.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Zhang, Juanjuan and Yan, Xuebin and Su, Fanglong and Li, Zhen and Wang, Ying and Wei, Yanan and Ji, Yangguang and Yang, Yi and Zhou, Xianhui and Guo, Hui and et al.}, year={2018}, month={Jun}, pages={440–448} }
 @article{shen_tian_zhang_tang_su_zhang_li_hu_hou_2018, title={Mechanisms of biochar assisted immobilization of Pb 2+ by bioapatite in aqueous solution}, volume={190}, ISSN={0045-6535}, url={http://dx.doi.org/10.1016/J.CHEMOSPHERE.2017.09.140}, DOI={10.1016/J.CHEMOSPHERE.2017.09.140}, abstractNote={Bioapatite (BAp) is regarded as an effective material to immobilize lead (Pb2+) via the formation of stable pyromorphite. However, when applied in contaminated soil, due to its low surface area and low adsorption capacity, BAp might not sufficiently contact and react with Pb2+. Biochar, a carbon storage material, typically has high surface area and high adsorption capacity. This study investigated the feasibility of using biochar as a reaction platform to enhance BAp immobilization of Pb2+. An alkaline biochar produced from wheat straw pellets (WSP) and a slightly acidic biochar produced from hardwood (SB) were selected. The results of aqueous adsorption showed the combination of biochar (WSP or SB) and BAp effectively removed Pb2+ from the aqueous solution containing 1000 ppm Pb2+. XRD, ATR-IR, and SEM/EDX results revealed the formation of hydroxypyromorphite on both biochars’ surfaces. This study demonstrates that biochars could act as an efficient reaction platform for BAp and Pb2+ in aqueous solution due to their high surface area, porous structure, and high adsorption capacity. Therefore, it is mechanistically feasible to apply biochar to enhance BAp immobilization of Pb2+ in contaminated soil.}, journal={Chemosphere}, publisher={Elsevier BV}, author={Shen, Zhengtao and Tian, Da and Zhang, Xinyu and Tang, Lingyi and Su, Mu and Zhang, Li and Li, Zhen and Hu, Shuijin and Hou, Deyi}, year={2018}, month={Jan}, pages={260–266} }
 @article{ye_chen_hall_pan_yan_bai_guo_zhang_bai_hu_2018, title={Reconciling multiple impacts of nitrogen enrichment on soil carbon: plant, microbial and geochemical controls}, volume={21}, ISSN={["1461-0248"]}, DOI={10.1111/ele.13083}, abstractNote={Impacts of reactive nitrogen (N) inputs on ecosystem carbon (C) dynamics are highly variable, and the underlying mechanisms remain unclear. Here, we proposed a new conceptual framework that integrates plant, microbial and geochemical mechanisms to reconcile diverse and contrasting impacts of N on soil C. This framework was tested using long-term N enrichment and acid addition experiments in a Mongolian steppe grassland. Distinct mechanisms could explain effects of N on particulate and mineral-associated soil C pools, potentially explaining discrepancies among previous N addition studies. While plant production predominated particulate C changes, N-induced soil acidification strongly affected mineral-associated C through decreased microbial growth and pH-sensitive associations between iron and aluminium minerals and C. Our findings suggest that effects of N-induced acidification on microbial respiration and geochemical properties should be included in Earth system models that predict ecosystem C budgets under future N deposition/input scenarios.}, number={8}, journal={ECOLOGY LETTERS}, author={Ye, Chenglong and Chen, Dima and Hall, Steven J. and Pan, Shang and Yan, Xuebin and Bai, Tongshuo and Guo, Hui and Zhang, Yi and Bai, Yongfei and Hu, Shuijin}, year={2018}, month={Aug}, pages={1162–1173} }
 @article{tian_wang_su_zheng_wu_wang_li_hu_2018, title={Remediation of lead-contaminated water by geological fluorapatite and fungus Penicillium oxalicum}, volume={25}, ISSN={0944-1344 1614-7499}, url={http://dx.doi.org/10.1007/S11356-018-2243-4}, DOI={10.1007/S11356-018-2243-4}, number={21}, journal={Environmental Science and Pollution Research}, publisher={Springer Science and Business Media LLC}, author={Tian, Da and Wang, Wenchao and Su, Mu and Zheng, Junyi and Wu, Yuanyi and Wang, Shimei and Li, Zhen and Hu, Shuijin}, year={2018}, month={May}, pages={21118–21126} }
 @article{zhang_zhang_zou_han_yan_li_hu_2018, title={Semi-quantitative analysis of microbial production of oxalic acid by montmorillonite sorption and ATR-IR}, volume={162}, ISSN={["1872-9053"]}, DOI={10.1016/j.clay.2018.07.006}, abstractNote={Interactions between organic acids and clay minerals significantly influence elemental cycle on Earth. Oxalic acid has been recognized as one of the most important secretions of soil microorganisms, for both typical bacterium Enterobacter sp. and fungus Aspergillus niger. This study examined the ATR-IR spectra of solid and aqueous oxalic acid. Then, sorption of dissolved oxalic acid, microbial secretion, and simulative acid solution onto montmorillonite were also studied by ATR-IR. The sorption significantly elevated intensity of the characteristic peak of oxalate at 1318 cm−1. Then, the intensity ratio (R) of 1318/1635 cm−1 was proposed as an accurate indicator for semi-quantitatively analyzing oxalic acid concentration. R values of ~0.13 and ~0.20 (for non-microorganism system) represented the oxalic acid concentrations of 600–800 ppm and ~2000 ppm respectively. Additionally, only oxalic acid with >800 ppm concentration can be identified appropriately if mixed with montmorillonite for 6 or 12 h, whereas 24 h shaking can decrease the detection line to as low as 100 ppm. Finally, we proposed an equation of Rcorrection = C0 ∗ Rmicrobe oxalic (with a coefficient C0 of 3.171) to estimate oxalic acid secreted by microorganisms. The coefficient was necessary due to the interference from multiple organic acids in microbial secretion. This equation worked successfully for both Enterobacter sp. and Aspergillus niger. It therefore is a reliable method for semi-quantitatively estimating microbial production of oxalic acid via montmorillonite sorption and ATR-IR technique.}, journal={APPLIED CLAY SCIENCE}, author={Zhang, Xinyu and Zhang, Lin and Zou, Xiang and Han, Feiyu and Yan, Ziping and Li, Zhen and Hu, Shuijin}, year={2018}, month={Sep}, pages={518–523} }
 @article{tao_bai_xiao_wang_wang_duryee_wang_zhang_hu_2018, title={Vertical distribution of ammonia-oxidizing microorganisms across a soil profile of the Chinese Loess Plateau and their responses to nitrogen inputs}, volume={635}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2018.04.104}, abstractNote={Ammonia-oxidizing archaea (AOA) and bacteria (AOB) oxidize ammonia into nitrite, the first and rate-limiting step of microbial nitrification, and exert major controls over soil nitrogen transformations. The Loess Plateau in northwest China is characterized with deep soils that are often exposed to the surface and reactive nitrogen (N) inputs due to erosion and human removal of the surface soil. However, few have examined the distribution of AOA and AOB along the profile of Loess Plateau soils and their responses to N inputs. We examined the abundance and diversity of AOA and AOB along the soil profile (0-100cm) and their responses to two levels of N inputs (low at 10, and high at 100μgNg-1 soil) in a 55-d incubation experiment. While AOB were most numerous in the surface soil (0-20cm), AOA were most abundant in the subsoils (20-40 and 40-60cm), suggesting a niche differentiation between AOA and AOB along the soil profile. High N input increased AOB nearly ten-fold in the upper two layers of soils (0-20 and 20-40cm) and sixteen to twenty-five fold in the deeper soil layers (40-60, 60-80 and 80-100cm). However, it only increased AOA by 7% (40-60cm) to 48% (20-40cm). In addition, potential nitrification rate and N2O emissions correlated only with AOB. Finally, high N input significantly increased AOB diversity and led to nitrite accumulation in deep soil layers (60-80 and 80-100cm). Together, our results showed that high N input can significantly alter the diversity and function of ammonia-oxidizing microbes in the deep soil of Loess Plateau, suggesting the need to examine the generality of the observed changes and their potential environmental impacts.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Tao, Jinjin and Bai, Tongshuo and Xiao, Rui and Wang, Peng and Wang, Fuwei and Duryee, Alexander M. and Wang, Yi and Zhang, Yi and Hu, Shuijin}, year={2018}, month={Sep}, pages={240–248} }
 @article{wang_li_xing_ma_hu_tu_2017, title={Bio-organic Fertilizer Promotes Plant Growth and Yield and Improves Soil Microbial Community in Continuous Monoculture System of Chrysanthemum morifolium cv. Chuju}, volume={19}, ISSN={["1814-9596"]}, DOI={10.17957/ijab/15.0339}, number={3}, journal={INTERNATIONAL JOURNAL OF AGRICULTURE AND BIOLOGY}, author={Wang, Jianfei and Li, Xiaoliang and Xing, Suzhi and Ma, Zhongyou and Hu, Shuijin and Tu, Cong}, year={2017}, pages={563–568} }
 @article{liu_wang_yan_li_jiao_hu_2017, title={Biochar amendments increase the yield advantage of legume-based intercropping systems over monoculture}, volume={237}, ISSN={["1873-2305"]}, DOI={10.1016/j.agee.2016.12.026}, abstractNote={Abstract Biochar soil amendments are receiving increased attention as one strategy to improve soil quality and crop productivity. However, studies about how biochar affects crop productivity so far have mainly focused on single cropping systems. Few have examined the effects of biochar additions on intercrops. We conducted a field experiment that investigated the effects of biochar amendments on yield and nutrient uptake in an intercropping system where maize (Zea mays L.) was intercropped with either soybean (Glycine max L.) or peanut (Arachis hypogaea L.). The relative advantages of both yield and total nutrient content were calculated as land equivalent ratios (LER). Biochar amendments significantly increased the yield advantage in both maize/soybean and maize/peanut systems over the single crops. Similarly, they significantly enhanced the relative N and P uptake advantage. Using the 15N isotope dilution method, we examined the effect of biochar amendments on peanut N2-fixation and subsequent N transfer from peanut to maize in a root-box experiment. Biochar amendments of 10 and 20 g kg−1 soil increased peanut N fixation by 15.52% and 14.11%, and increased N transfer from peanut to maize by 32.66% and 36.07%, respectively. These results indicate that amending soil with biochar can amplify the benefits of legume-based intercropping by enhancing legume N fixation and facilitating N transfer from legume plants to co-existing cereal crops.}, journal={AGRICULTURE ECOSYSTEMS & ENVIRONMENT}, author={Liu, Ling and Wang, Yanfang and Yan, Xinwei and Li, Jiwei and Jiao, Nianyuan and Hu, Shuijin}, year={2017}, month={Jan}, pages={16–23} }
 @article{wu_chen_tu_qiu_burkey_reberg-horton_peng_hu_2017, title={CO2-induced alterations in plant nitrate utilization and root exudation stimulate N2O emissions}, volume={106}, ISSN={["0038-0717"]}, DOI={10.1016/j.soilbio.2016.11.018}, abstractNote={Atmospheric carbon dioxide enrichment (eCO2) often increases soil nitrous oxide (N2O) emissions, which has been largely attributed to increased denitrification induced by CO2-enhancement of soil labile C and moisture. However, the origin of the N remains unexplained. Emerging evidence suggests that eCO2 alters plant N preference in favor of ammonium (NH4+-N) over nitrate (NO3−-N). Yet, whether and how this attributes to the enhancement of N2O emissions has not been investigated. We conducted a microcosm experiment with wheat (Triticum aestivum L.) and tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) to examine the effects of eCO2 on soil N2O emissions in the presence of two N forms (NH4+-N or NO3−-N). Results obtained showed that N forms dominated eCO2 effects on plant and microbial N utilization, and thus soil N2O emissions. Elevated CO2 significantly increased the rate and the sum of N2O emissions by three to four folds when NO3−-N, but not NH4+-N, was supplied under both wheat and tall fescue. While enhanced N2O emission was more related to the reduced plant NO3−-N uptake under wheat, it concurred with increased labile C under tall fescue. In the presence of NO3−-N, significantly lower shoot biomass N and 15N, but higher plant biomass C:N ratio, microbial biomass C and N, and/or soil extractable C indicated that eCO2 constrained plant NO3−-N utilization and likely stimulated root exudation. We propose a new conceptual model in which eCO2-inhibition of plant NO3−-N uptake and/or CO2-enhancement of soil labile C enhances the N and/or C availability for denitrifiers and increases the intensity and/or the duration of N2O emissions. Together, these findings indicate that CO2-enhancement of soil N and labile C favors denitrification, suggesting that management of N fertilizers in intensive systems will likely become more challenging under future CO2 scenarios.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Wu, Keke and Chen, Dima and Tu, Cong and Qiu, Yunpeng and Burkey, Kent O. and Reberg-Horton, S. Chris and Peng, Shaolin and Hu, Shuijin}, year={2017}, month={Mar}, pages={9–17} }
 @article{xie_zhou_li_hu_zhang_zhang_wang_kong_2017, title={Characterization of ferulic acid removal from aqueous solution by H2O2-modified hydrothermal biochar produced from Chrysanthemum morifolium Ramat. cv. Chuju}, volume={26}, number={12}, journal={Fresenius Environmental Bulletin}, author={Xie, Y. and Zhou, C. and Li, F. Y. and Hu, S. J. and Zhang, Z. L. and Zhang, Z. and Wang, J. F. and Kong, W. F.}, year={2017}, pages={7478–7491} }
 @article{li_tang_zheng_tian_su_zhang_ma_hu_2017, title={Characterizing the Mechanisms of Lead Immobilization via Bioapatite and Various Clay Minerals}, volume={1}, ISSN={["2472-3452"]}, DOI={10.1021/acsearthspacechem.7b00016}, abstractNote={Immobilizing lead (Pb) in contaminated water and soils via mineralization is an emerging field of interest in environmental remediation. This study investigated the feasibility of applying bioapatite and typical clay minerals (kaolinite, palygorskite, and montmorillonite) to immobilize Pb2+ cations in water. The mechanisms of lead immobilization were studied by inductively coupled plasma optical emission spectrometry (ICP–OES), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). Montmorillonite shows the highest efficiency in Pb remediation (reduced from ∼2000 to 30 ppm) with the addition of bioapatite. The XRD and HRTEM results demonstrated that aqueous Pb removal efficiency is facilitated by bioapatite via reacting with Pb to form pyromorphite mineral [Pb5(PO4)3(F,Cl,OH)]. The high surface area and cation-exchange capability of montmorillonite allow its abundant absorption of Pb2+ and, hence, cause the enriched formation of pyromorphite on its surface. In contrast, the...}, number={3}, journal={ACS EARTH AND SPACE CHEMISTRY}, author={Li, Zhen and Tang, Lingyi and Zheng, Yangfan and Tian, Da and Su, Mu and Zhang, Fan and Ma, Shuojia and Hu, Shuijin}, year={2017}, month={May}, pages={152–157} }
 @article{ling_chen_guo_wei_bai_shen_hu_2017, title={Differential responses of soil bacterial communities to long-term N and P inputs in a semi-arid steppe}, volume={292}, ISSN={["1872-6259"]}, DOI={10.1016/j.geoderma.2017.01.013}, abstractNote={Abstract Both nitrogen (N) and phosphorus (P) may limit plant production in steppes and affect plant community structure. However, few studies have explored in detail the differences and similarities in the responses of belowground microbial communities to long-term N and P inputs. Using a high-throughput Illumina Miseq sequencing platform, we characterized the bacterial communities in a semi-arid steppe subjected to long-term N or P additions. Our results showed that both the Chao richness and Shannon's diversity were negatively correlated to N input rate, while only Chao richness was significantly and negatively correlated to P input rate. Also, both N and P additions altered the bacterial community structure. The bacterial community between plots of the same N or P input rate was much more dissimilar with the higher input level, indicating more severe niche differentiation in pots with higher N or P input. N Inputs significantly increased the relative abundance of the predicted copiotrophic groups (Proteobacteria and Firmicutes) but reduced the predicted oligotrophic groups (Acidobacteria, Nitrospirae, Chloroflexi), with the order Rhizobiales being most affected. P additions significantly affected only two phyla (Armatimonadetes and Chlorobi), which were positively correlated with P source. Results from the structural equation modelling (SEM) showed that N additions affected the bacterial community primarily by changing the pH, while P additions did so mainly by improving P availability. Our results suggest that the below-ground bacterial communities are more sensitive to N inputs, but P inputs can also play an important role in bacterial niche differentiation. These findings improve our understanding of bacterial responses to N and P inputs, and their impacts on bacterial-mediated processes, especially in the context of increasing anthropogenic nutrient inputs.}, journal={GEODERMA}, author={Ling, Ning and Chen, Dima and Guo, Hui and Wei, Jiaxin and Bai, Yongfei and Shen, Qirong and Hu, Shuijin}, year={2017}, month={Apr}, pages={25–33} }
 @article{li_su_tian_tang_zhang_zheng_hu_2017, title={Effects of elevated atmospheric CO2 on dissolution of geological fluorapatite in water and soil}, volume={599}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2017.05.100}, abstractNote={Most of phosphorus (P) is present as insoluble phosphorus-bearing minerals or organic forms in soil. Geological fluorapatite (FAp) is the dominant mineral-weathering source of P. In this study, FAp was added into water and soil under elevated CO2 to investigate the pathway of P release. Two types of soils (an acidic soil from subtropical China and a saline-alkali soil from Tibet Plateau, China) with similar total P content were studied. In the solution, increased CO2 in air enhanced the dissolution of FAp, i.e., from 0.04 to 1.18ppm for P and from 2.48 to 13.61ppm for Ca. In addition, release of Ca and P from FAp reached the maximum (2.14ppm for P and 13.84ppm for Ca) under the combination of elevated CO2 and NaCl due to the increasing ion exchange. Consistent with the results from the solution, CO2 elevation promoted P release more significantly (triple) in the saline-alkali soil than in the acidic soil. Therefore, saline-alkali soils in Tibet Plateau would be an important reservoir of available P under the global CO2 rise. This study sheds the light on understanding the geological cycle of phosphorus.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Li, Zhen and Su, Mu and Tian, Da and Tang, Lingyi and Zhang, Lin and Zheng, Yangfan and Hu, Shuijin}, year={2017}, month={Dec}, pages={1382–1387} }
 @article{zheng_mamuti_liu_shu_hu_wang_li_lin_li_2017, title={Effects of nutrient additions on litter decomposition regulated by phosphorus-induced changes in litter chemistry in a subtropical forest, China}, volume={400}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2017.06.002}, abstractNote={Nutrient additions directly alter exogenous nutrient availability in soil, and then affect endogenous nutrient concentration in litter (i.e., litter chemistry), modifying litter decomposition. However, how nutrient-induced changes in litter chemistry interacting with altered soil nutrients affect litter decomposition remain unclear. In this study, three field experiments with reciprocal transplants using litter bags were conducted in a phosphorous (P) limiting subtropical forest with control, nitrogen addition (+N), P addition (+P), and +NP treatments to examine effects of exogenous and endogenous nutrient availability on litter decomposition. Our results showed that, in Experiment I, decomposition of litter collected from the control plots was significantly inhibited by 16% under both +P and +NP treatments and reversed to become net P accumulation from P release compared to that in the control. In Experiment II, since litter collected from +P and +NP plots had higher litter P, lower C/P and N/P, its decomposition was significantly faster in the control plots by 9% and 26%, respectively, with the faster release of N and P in the litter. The in situ Experiment III found that +P and +NP treatments reduced litter decomposition by 6% and 14%, respectively, but +N did not affect it compared to the control. Our results indicate that effects of P addition on litter decomposition were mediated by P-induced changes in litter chemistry, which need to be incorporated into land surface models for predicting effects of nutrient deposition on ecosystem C cycling and assessing the climate-biosphere feedbacks. Effects of nutrient additions on litter decomposition were regulated by P-induced changes in litter chemistry.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Zheng, Zemei and Mamuti, Meiliban and Liu, Heming and Shu, Yuqin and Hu, Shuijin and Wang, Xihua and Li, Binbin and Lin, Li and Li, Xu}, year={2017}, month={Sep}, pages={123–128} }
 @article{pan_liu_mo_patterson_duan_tian_hu_tang_2017, title={Erratum: Corrigendum: Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes}, volume={7}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/SREP45611}, DOI={10.1038/SREP45611}, abstractNote={Scientific Reports 6: Article number: 32148; published online: 25 August 2016; updated: 30 March 2017 The original version of this Article contained a typographical error in the spelling of the author Shuijin Hu, which was incorrectly given as Shuijing Hu. This has now been corrected in the PDF and HTML versions of the Article.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Pan, Shenggang and Liu, Haidong and Mo, Zhaowen and Patterson, Bob and Duan, Meiyang and Tian, Hua and Hu, Shuijin and Tang, Xiangru}, year={2017}, month={Mar} }
 @article{jiang_groenigen_huang_hungate_kessel_hu_zhang_wu_yan_wang_et al._2017, title={Higher yields and lower methane emissions with new rice cultivars}, volume={23}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.13737}, abstractNote={Breeding high-yielding rice cultivars through increasing biomass is a key strategy to meet rising global food demands. Yet, increasing rice growth can stimulate methane (CH4) emissions, exacerbating global climate change, as rice cultivation is a major source of this powerful greenhouse gas. Here, we show in a series of experiments that high-yielding rice cultivars actually reduce CH4 emissions from typical paddy soils. Averaged across 33 rice cultivars, a biomass increase of 10% resulted in a 10.3% decrease in CH4 emissions in a soil with a high carbon (C) content. Compared to a low-yielding cultivar, a high-yielding cultivar significantly increased root porosity and the abundance of methane-consuming microorganisms, suggesting that the larger and more porous root systems of high-yielding cultivars facilitated CH4 oxidation by promoting O2 transport to soils. Our results were further supported by a meta-analysis, showing that high-yielding rice cultivars strongly decrease CH4 emissions from paddy soils with high organic C contents. Based on our results, increasing rice biomass by 10% could reduce annual CH4 emissions from Chinese rice agriculture by 7.1%. Our findings suggest that modern rice breeding strategies for high-yielding cultivars can substantially mitigate paddy CH4 emission in China and other rice growing regions.}, number={11}, journal={GLOBAL CHANGE BIOLOGY}, author={Jiang, Yu and Groenigen, Kees Jan and Huang, Shan and Hungate, Bruce A. and Kessel, Chris and Hu, Shuijin and Zhang, Jun and Wu, Lianhai and Yan, Xiaojun and Wang, Lili and et al.}, year={2017}, month={Nov}, pages={4728–4738} }
 @article{wells_reberg-horton_mirsky_maul_hu_2017, title={In situ validation of fungal N translocation to cereal rye mulches under no-till soybean production}, volume={410}, ISSN={0032-079X 1573-5036}, url={http://dx.doi.org/10.1007/S11104-016-2989-8}, DOI={10.1007/S11104-016-2989-8}, abstractNote={The ability of grass mulches to inhibit weed performance has been linked to their limitations on nitrogen availability to the weeds. Fungal translocation of N from the soil to the surface mulch has been confirmed in laboratories, but this mechanism has not been documented under field conditions. Experiments used 15N (NH4)2SO4 , 99.7 at.%, which was uniformly injected below the soil surface at a rate of 1 mg 15 N kg−1 soil. Some plots were treated with a fungicide (Captan) every 2 weeks after injection, while others were not treated. Nitrogen transfer was monitored by measuring levels in surface residue, soybean tissue, and extractable soil inorganic N pools. Despite the N release from the cereal rye (Secale cereale L.) tissues ranging from 15 to 50 kg N ha−1, there was a detectable increase in 15N enrichment of 10–15 % in the cereal rye tissue. Six weeks after injection, tissue from the plots not treated with fungicide contained 36 % more 15 N. The increased 15N enrichment in the cereal rye mulch supports laboratory observations that soil inorganic N is translocated into surface mulch via fungal mechanisms. These findings illustrate microbial-mediated sinks for nitrogen in cereal rye mulches in no-till soybean production systems.}, number={1-2}, journal={Plant and Soil}, publisher={Springer Nature}, author={Wells, M. Scott and Reberg-Horton, S. Chris and Mirsky, Steven B. and Maul, Jude E. and Hu, Shuijin}, year={2017}, pages={153–165} }
 @article{guo_ye_zhang_pan_ji_li_liu_zhou_du_hu_et al._2017, title={Long-term nitrogen & phosphorus additions reduce soil microbial respiration but increase its temperature sensitivity in a Tibetan alpine meadow}, volume={113}, ISSN={["0038-0717"]}, DOI={10.1016/j.soilbio.2017.05.024}, abstractNote={Nutrient availability may exert major controls over soil microbial respiration, especially in carbon (C)-rich, nitrogen (N)-limited ecosystems in high elevation regions, but how soil organic matter (SOM) decomposition and its temperature sensitivity respond to long-term N & P additions in alpine ecosystems remains unclear. We examined the impact of long-term (15 yr) N & P additions on soil microbial respiration and its temperature sensitivity (Q10), and assessed the relative importance of nutrient-induced alterations in substrate quality and the microbial community composition in explaining the variation in soil respiration and temperature sensitivity. We found that N & P additions significantly reduced microbial respiration rates and cumulative C efflux, but increased the Q10 (15/5 °C). Also, N & P additions reduced the biomass of the whole microbial community, gram negative bacteria and fungi, but increased the aromaticity and aliphaticity of soil organic C substrate. Across the treatments, averaged Q10 was positively correlated with the complexity of SOM as characterized by 13C-NMR, supporting the prediction based on kinetic theory that SOM with recalcitrant molecular structure is with high temperature sensitivity. Together, our results showed that changes in both substrate quality and soil microbial community induced by long-term nutrient inputs may alter the response of soil microbial respiration to elevated temperature. Because the positive effects of increasing temperature sensitivity for use of lower quality substrates on C emission may be offset by lower absolute rates at any one temperature, long-term N & P additions increase the uncertainty in predicting the net soil C losses in the scenario of warming on Tibetan Plateau.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Guo, Hui and Ye, Chenglong and Zhang, Hao and Pan, Shang and Ji, Yangguang and Li, Zhen and Liu, Manqiang and Zhou, Xianhui and Du, Guozhen and Hu, Feng and et al.}, year={2017}, month={Oct}, pages={26–34} }
 @article{wang_li_tu_hoyt_deforest_hu_2017, title={Long-term no-tillage and organic input management enhanced the diversity and stability of soil microbial community}, volume={609}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2017.07.053}, abstractNote={Intensive tillage and high inputs of chemicals are frequently used in conventional agriculture management, which critically depresses soil properties and causes soil erosion and nonpoint source pollution. Conservation practices, such as no-tillage and organic farming, have potential to enhance soil health. However, the long-term impact of no-tillage and organic practices on soil microbial diversity and community structure has not been fully understood, particularly in humid, warm climate regions such as the southeast USA. We hypothesized that organic inputs will lead to greater microbial diversity and a more stable microbial community, and that the combination of no-tillage and organic inputs will maximize soil microbial diversity. We conducted a long-term experiment in the southern Appalachian mountains of North Carolina, USA to test these hypotheses. The results showed that soil microbial diversity and community structure diverged under different management regimes after long term continuous treatments. Organic input dominated the effect of management practices on soil microbial properties, although no-tillage practice also exerted significant impacts. Both no-tillage and organic inputs significantly promoted soil microbial diversity and community stability. The combination of no-tillage and organic management increased soil microbial diversity over the conventional tillage and led to a microbial community structure more similar to the one in an adjacent grassland. These results indicate that effective management through reducing tillage and increasing organic C inputs can enhance soil microbial diversity and community stability.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Wang, Yi and Li, Chunyue and Tu, Cong and Hoyt, Greg D. and DeForest, Jared L. and Hu, Shuijin}, year={2017}, month={Dec}, pages={341–347} }
 @article{zeng_yang_xuan_dai_hu_hu_zhong_li_gao_wang_et al._2017, title={Longitudinal Study of the Effects of Environmental pH on the Mechanical Properties of Aspergillus niger}, volume={3}, ISSN={["2373-9878"]}, DOI={10.1021/acsbiomaterials.6b00294}, abstractNote={The regulation of environmental pH is key to the health of an ecosystem, influencing the metabolic activity, growth, and development of organisms within it. Although pH values can be measured by a wide range of readily available technologies ranging from fluorescent dyes and nanosensors, these cannot reveal the history of environmental pH from before monitoring begins. This information is sometimes crucial for piecing together what has happened to an ecosystem, and our long-term goal is therefore to develop technologies capable of obtaining it. Here, we propose monitoring environmental pH over time by tracking mechanical properties of a common fungus. As a first step toward obtaining a time history of pH, we evaluate the effect of pH upon the effective indentation modulus of spores and hyphae of Aspergillus niger. We report that the indentation modulus of this phosphorus-solubilizing fungus, obtained through atomic force microscopy and nanoindentation, correlated with environmental acidity. We observed a significant, monotonic increase in moduli over the course of incubation in an acidic environment, but no change in moduli over time for incubation in a neutral environment. Results show promise for using our scheme to detect and track environmental pH over time, and more broadly for using a microorganism’s mechanical properties as a biomarker for environmental detection.}, number={11}, journal={ACS BIOMATERIALS SCIENCE & ENGINEERING}, author={Zeng, Wenjun and Yang, Hua and Xuan, Guanghui and Dai, Letian and Hu, Yunxiao and Hu, Shuijin and Zhong, Shengkui and Li, Zhen and Gao, Mingyuan and Wang, Shimei and et al.}, year={2017}, month={Nov}, pages={2974–2979} }
 @article{yu_xiao_hu_polizzotto_zhao_mcgrath_li_ran_shen_2017, title={Mineral Availability as a Key Regulator of Soil Carbon Storage}, volume={51}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.7b00305}, abstractNote={Mineral binding is a major mechanism for soil carbon (C) stabilization, and mineral availability for C binding critically affects C storage. Yet, the mechanisms regulating mineral availability are poorly understood. Here, we showed that organic amendments in three long-term (23, 154, and 170 yrs, respectively) field experiments significantly increased mineral availability, particularly of short-range-ordered (SRO) phases. Two microcosm studies demonstrated that the presence of roots significantly increased mineral availability and promoted the formation of SRO phases. Mineral transformation experiments and isotopic labeling experiments provided direct evidence that citric acid, a major component of root exudates, promoted the formation of SRO minerals, and that SRO minerals acted as "nuclei" for C retention. Together, these findings indicate that soil organic amendments initialize a positive feedback loop by increasing mineral availability and promoting the formation of SRO minerals for further C binding, thereby possibly serving as a management tool for enhancing carbon storage in soils.}, number={9}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yu, Guanghui and Xiao, Jian and Hu, Shuijin and Polizzotto, Matthew L. and Zhao, Fangjie and McGrath, Steve P. and Li, Huan and Ran, Wei and Shen, Qirong}, year={2017}, month={May}, pages={4960–4969} }
 @article{ye_bai_yang_zhang_guo_li_li_hu_2017, title={Physical access for residue-mineral interactions controls organic carbon retention in an Oxisol soil}, volume={7}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-017-06654-6}, abstractNote={Abstract Oxisol soils are widely distributed in the humid tropical and subtropical regions and are generally characterized with high contents of metal oxides. High metal oxides are believed to facilitate organic carbon (C) accumulation via mineral-organic C interactions but Oxisols often have low organic C. Yet, the causes that constrain organic C accumulation in Oxisol soil are not exactly clear. Here we report results from a microcosm experiment that evaluated how the quantity and size of crop residue fragments affect soil C retention in a typical Oxisol soil in southeast China. We found that there were significantly higher levels of dissolved organic C (DOC), microbial biomass C (MBC) and C accumulation in the heavy soil fraction in soil amended with fine-sized (<0.2 mm) compared with coarse-sized (5.0 mm) fragments. Attenuated total reflectance-Fourier transform infrared spectroscopy analysis further showed that fine-sized residues promoted stabilization of aliphatic C-H and carboxylic C=O compounds associated with mineral phases. In addition, correlation analysis revealed that the increased content of organic C in the heavy soil fraction was positively correlated with increased DOC and MBC. Together, these results suggest that enhancement of contact between organic materials and soil minerals may promote C stabilization in Oxisols.}, journal={SCIENTIFIC REPORTS}, author={Ye, Chenglong and Bai, Tongshuo and Yang, Yi and Zhang, Hao and Guo, Hui and Li, Zhen and Li, Huixin and Hu, Shuijin}, year={2017}, month={Jul} }
 @article{hu_zhu_chen_bonkowski_griffiths_chen_zhu_hu_hu_liu_2017, title={Responses of rice paddy micro-food webs to elevated CO2 are modulated by nitrogen fertilization and crop cultivars}, volume={114}, ISSN={0038-0717}, url={http://dx.doi.org/10.1016/J.SOILBIO.2017.07.008}, DOI={10.1016/J.SOILBIO.2017.07.008}, abstractNote={Elevated atmospheric CO2 concentrations (eCO2) often increase plant growth but simultaneously lead to the nitrogen (N) limitation in soil. The corresponding mitigation strategy such as supplementing N fertilizer and growing high-yielding cultivars at eCO2 would further modify soil ecosystem structure and function. Little attention has, however, been directed toward assessing the responses of soil food web. We report results from a long-term free air CO2 enrichment (FACE) experiment in a rice paddy agroecosystem that examined the responses of soil micro-food webs to eCO2 and exogenous nitrogen fertilization (eN) in the rhizosphere of two rice cultivars with distinctly weak and strong responses to eCO2. Soil micro-food web parameters, including microfauna (protists and nematodes) and soil microbes (bacteria and fungi from phospholipid fatty acid (PLFA) analysis), as well as soil C and N variables, were determined at the heading and ripening stages of rice. Results showed that eCO2 effects on soil micro-food webs depended strongly on N fertilization, rice cultivar and growth stage. eCO2 stimulated the fungal energy channel at the ripening stage, as evidenced by increases in fungal biomass (32%), fungi:bacteria ratio (18%) and the abundance of fungivorous nematodes (64%), mainly due to an enhanced carbon input. The eN fueled the bacterial energy channel by increasing the abundance of flagellates and bacterivorous nematodes, likely through alleviating the N-limitation of plants and rhizosphere under eCO2. While eCO2 decreased the abundance of herbivorous nematodes under the weak-responsive cultivar by 59% and 47% with eN at the heading and ripening stage, respectively, the numbers of herbivorous nematodes almost tripled (×2.9; heading) and doubled (×1.6; ripening) under the strong-responsive cultivar with eCO2 at eN due to higher root quantity and quality. Structural equation model (SEM) showed that lower trophic-level organisms were affected by bottom-up forces of altered soil resources induced by eCO2 and eN, and effects on higher trophic level organisms were driven by bottom-up cascades with 69% of the variation being explained. Taken together, strategies to adapt climate change by growing high-yielding crop cultivars under eCO2 may face a trade-off by negative soil feedbacks through the accumulation of root-feeding crop pest species.}, journal={Soil Biology and Biochemistry}, publisher={Elsevier BV}, author={Hu, Zhengkun and Zhu, Chunwu and Chen, Xiaoyun and Bonkowski, Michael and Griffiths, Bryan and Chen, Fajun and Zhu, Jianguo and Hu, Shuijin and Hu, Feng and Liu, Manqiang}, year={2017}, month={Nov}, pages={104–113} }
 @article{yang_zhang_koide_hoeksema_tang_bian_hu_chen_2017, title={Taxonomic resolution is a determinant of biodiversity effects in arbuscular mycorrhizal fungal communities}, volume={105}, ISSN={["1365-2745"]}, DOI={10.1111/1365-2745.12655}, abstractNote={Arbuscular mycorrhizal fungi (AMF) are key regulators of ecosystem processes, yet how their biodiversity works in ecosystems remains poorly understood. We documented the extent to which taxonomic resolution influenced the effect of biodiversity of AMF taxa on plant performance (growth, nutrient uptake and stress tolerance) in a meta-analysis of 902 articles. We found that the effect of biodiversity of AMF taxa depended on taxonomic resolution. Plant performance was positively promoted by AMF family richness, while no effect was found for fungal species richness. In addition, negative effect was found between AMF phylogenetic diversity and plant growth. This pattern can be explained by functional conservatism within AMF families and functional differentiation among AMF families. Synthesis. Conservation of AMF communities to maintain a full complement of ecosystem functions requires the presence of diverse families and not simply diverse species within a family. This finding may be of key importance for the function of ecosystems under various environmental perturbations to which AMF families may respond differently.}, number={1}, journal={JOURNAL OF ECOLOGY}, author={Yang, Haishui and Zhang, Qian and Koide, Roger T. and Hoeksema, Jason D. and Tang, Jianjun and Bian, Xinmin and Hu, Shuijin and Chen, Xin}, year={2017}, month={Jan}, pages={219–228} }
 @misc{chen_wang_meng_yang_jiang_zou_li_hu_2017, title={Temperature-related changes of Ca and P release in synthesized hydroxylapatite, geological fluorapatite, and bone bioapatite}, volume={451}, ISSN={["1878-5999"]}, DOI={10.1016/j.chemgeo.2017.01.014}, abstractNote={Solubility of apatite is highly addressed in mineralogical and material studies. Heating is one of the major processes in apatite industry. In this study, synthesized hydroxylapatite (HAp), geological fluorapatite (FAp), and bone bioapatite (BAp) were heated at various temperatures (100–900 °C) for analyses. The mineralogy and solubility of the three apatites were analyzed by XRD, ATR–IR, and ICP. Release of Ca and P in water for BAp reaches the maximum when heated at 200 °C, i.e., 0.215 mmol/L for Ca and 0.106 mmol/L for P. The value is higher than the maximum values (heated at 900 °C) of the solubility for HAp and FAp. The heating temperature at 600 °C is a re-crystallization point for all the three types of apatites. Especially, the crystallinity of BAp is significantly elevated at > 600 °C. Phase of geological FAp is relatively stable during heating up to 900 °C. Phase of β-TCP is present when heating HAp at 800 to 900 °C. In addition, BAp is transformed to the resemblance of HAp. However, no β-TCP was detected for BAp during heating between 800 and 900 °C, which is probably due to its Ca-deficiency. This study elucidates the correlation of phase changes of BAp and its solubility during heating, which sheds the light on its application as materials and fertilizer.}, journal={CHEMICAL GEOLOGY}, author={Chen, Weikun and Wang, Quanzhi and Meng, Shiting and Yang, Ping and Jiang, Liu and Zou, Xiang and Li, Zhen and Hu, Shuijin}, year={2017}, month={Feb}, pages={183–188} }
 @article{guo_hu_gao_xie_ling_shen_hu_guo_2017, title={The rice production practices of high yield and high nitrogen use efficiency in Jiangsu, China}, volume={7}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-017-02338-3}, abstractNote={Abstract To face the great challenges of ensuring food security and environmental sustainability, agricultural production must be improved by high yield and high resource utilization efficiency (HYHE). We recently addressed this challenge and evaluated yield potential by surveying 735 farmers in 2008–2012 and then conducting 6 rice field experiments in 2008–2013 with large demonstration areas in 2010–2013 aimed to actualize the HYHE in Jiangsu Province, China. The survey result showed that the averaged N rate, grain yield and N partial factor productivity (PFP N ) of the farmers were 336.7 kg ha −1 , 8131.8 kg ha −1 and 24.2 kg kg −1 , respectively. Through controlling total N rates and adjusting the application timing, the yield and the PFP N of optimal N managements (OPT) were increased by 5.9% and 37.6% with 31.4% reduction in N supply amounts for 6 experimental sites, and the yield increased by 5.6% for large demonstration areas compared with farmers’ fertilizer practices (FFP), respectively. In conclusion, although the soil properties of the different regions varied, HYHE could be achieved by regulating the N management practices, thus contributing to higher rice production and lower environmental costs from intensive agriculture in Jiangsu, China.}, journal={SCIENTIFIC REPORTS}, author={Guo, Jiuxin and Hu, Xiangyu and Gao, Limin and Xie, Kailiu and Ling, Ning and Shen, Qirong and Hu, Shuijin and Guo, Shiwei}, year={2017}, month={May} }
 @article{li_bai_dai_wang_tao_meng_hu_wang_hu_2016, title={A study of organic acid production in contrasts between two phosphate solubilizing fungi: Penicillium oxalicum and Aspergillus niger}, volume={6}, ISSN={["2045-2322"]}, DOI={10.1038/srep25313}, abstractNote={Abstract Phosphate solubilizing fungi (PSF) have huge potentials in enhancing release of phosphorus from fertilizer. Two PSF (NJDL-03 and NJDL-12) were isolated and identified as Penicillium oxalicum and Aspergillus niger respectively in this study. The quantification and identification of organic acids were performed by HPLC. Total concentrations of organic acids secreted by NJDL-03 and NJDL-12 are ~4000 and ~10,000 mg/L with pH values of 3.6 and 2.4 respectively after five-days culture. Oxalic acid dominates acidity in the medium due to its high concentration and high acidity constant. The two fungi were also cultured for five days with the initial pH values of the medium varied from 6.5 to 1.5. The biomass reached the maximum when the initial pH values are 4.5 for NJDL-03 and 2.5 for NJDL-12. The organic acids for NJDL-12 reach the maximum at the initial pH = 5.5. However, the acids by NJDL-03 continue to decrease and proliferation of the fungus terminates at pH = 2.5. The citric acid production increases significantly for NJDL-12 at acidic environment, whereas formic and oxalic acids decrease sharply for both two fungi. This study shows that NJDL-12 has higher ability in acid production and has stronger adaptability to acidic environment than NJDL-03.}, journal={SCIENTIFIC REPORTS}, author={Li, Zhen and Bai, Tongshuo and Dai, Letian and Wang, Fuwei and Tao, Jinjin and Meng, Shiting and Hu, Yunxiao and Wang, Shimei and Hu, Shuijin}, year={2016}, month={Apr} }
 @article{chen_cheng_chu_mi_hu_xie_tuvshintogtokh_bai_2016, title={Effect of diversity on biomass across grasslands on the Mongolian Plateau: contrasting effects between plants and soil nematodes}, volume={43}, ISSN={["1365-2699"]}, DOI={10.1111/jbi.12683}, abstractNote={Aim To assess how the diversity of above- and below-ground organisms changes along environmental gradients at the regional scale and whether the effects of diversity changes on biomass are similar for above- and below-ground organisms. Location Semi-arid grasslands of the Mongolian Plateau. Methods We investigated diversity (α-, β- and γ-) and biomass of plant and soil nematodes as well as environmental factors (climate, soil environment, and soil resource) at 44 field sites (220 plots) along a 2000-km east–west transect and a 900-km south–north transect across grasslands on the Mongolian Plateau. Regression was used to examine the relationships between diversity components and biomass of plants and nematodes. Hierarchical structural equation modelling (SEM) was performed to analyse the effects of environmental factors on diversity components and their linkages to biomass. Results The biomass of plants and nematodes correlated positively with biodiversity measures for plants and nematodes except that nematode biomass decreased as nematode β-diversity increased. The relationship between plant and soil nematodes was positive for biomass and for α- and γ-diversity, but it was negative for β-diversity. When considering the environmental factors, hierarchical SEM indicated that variation in plant or nematode γ-diversity was associated with changes in climate, soil environment, and soil resources. Variation in plant or nematode α-diversity was mainly associated with changes in γ-diversity, while variation in the plant or nematode β-diversity was mainly associated with changes in γ-diversity and climate. The climate and soil resources explained most of the variation in plant biomass, whereas climate and α- and γ-diversity explained most of the variation in nematode biomass. Surprisingly, plant biomass or diversity was only weakly related to soil nematodes when considering the environmental factors. Main conclusions Diversity and biomass patterns of nematodes and perhaps of other below-ground organisms are different from those of plants, and this difference is highly climate dependent. These findings suggest that a more complete understanding of diversity–biomass relationships will require further examination of more taxa across a broader range of environmental gradients.}, number={5}, journal={JOURNAL OF BIOGEOGRAPHY}, author={Chen, Dima and Cheng, Junhui and Chu, Pengfei and Mi, Jia and Hu, Shuijin and Xie, Yichun and Tuvshintogtokh, Indree and Bai, Yongfei}, year={2016}, month={May}, pages={955–966} }
 @article{pan_liu_mo_patterson_duan_tian_hu_tang_2016, title={Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes}, volume={6}, ISSN={["2045-2322"]}, DOI={10.1038/srep32148}, abstractNote={Abstract Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice.}, journal={SCIENTIFIC REPORTS}, author={Pan, Shenggang and Liu, Haidong and Mo, Zhaowen and Patterson, Bob and Duan, Meiyang and Tian, Hua and Hu, Shuijing and Tang, Xiangru}, year={2016}, month={Aug} }
 @article{hu_wang_gu_tao_zhang_hu_zhu_meng_2016, title={Effects of different straw returning modes on greenhouse gas emissions and crop yields in a rice-wheat rotation system}, volume={223}, ISSN={["1873-2305"]}, DOI={10.1016/j.agee.2016.02.027}, abstractNote={Significant efforts have been made to assess the common straw returning modes on crop yields and greenhouse gas (GHG) emissions. However, the effects of a novel straw returning mode, namely ditch-buried straw returning on GHG emissions are still unknown. We conducted a 2-year field experiment, including four wheat straw returning modes (no straw returning (CK), wheat straw returning with rotary tillage (WR), wheat straw returning with plowing (WP), and ditch-buried wheat straw returning (WD)) to evaluate crop yields and GHG emissions under rice–wheat rotation system. Methane (CH4) and nitrous oxide (N2O) fluxes were measured using the static chamber method from the 2013 rice season to 2015 wheat season. The results indicated that wheat straw returning treatments before rice transplantation significantly increased seasonal CH4 emissions during both the rice seasons and wheat seasons, compared to CK. Annual CH4 emission was lower under WD than that under WR and WP. Straw returning significantly increased N2O emission during the first rice season and second wheat season, compared to CK. Annual N2O emission under WD was significantly lower than that under WP, but significantly higher than that under WR and CK. Straw returning increased both rice and wheat yields compared with CK, and WD had significantly higher annual grain yields of both rice and wheat, with an increase of 7.1%. Across the two rotation cycles, annual yield-scaled GWP of CH4 and N2O emissions under WD was 10.8% lower than that of WR. These results indicated that compared with straw returning via rotary tillage or plowing, ditch-buried wheat straw in rice seasons may reduce GHG emissions while sustaining or even increasing crop yields in the rice–wheat rotation system.}, journal={AGRICULTURE ECOSYSTEMS & ENVIRONMENT}, author={Hu, Naijuan and Wang, Baojun and Gu, Zehai and Tao, Baorui and Zhang, Zhengwen and Hu, Shuijin and Zhu, Liqun and Meng, Yali}, year={2016}, month={May}, pages={115–122} }
 @article{chen_pan_bai_hu_huang_wang_naeem_elser_wu_han_2016, title={Effects of plant functional group loss on soil biota and net ecosystem exchange: a plant removal experiment in the Mongolian grassland}, volume={104}, ISSN={["1365-2745"]}, DOI={10.1111/1365-2745.12541}, abstractNote={The rapid loss of global biodiversity can greatly affect the functioning of above-ground components of ecosystems. However, how such biodiversity losses affect below-ground communities and linkages to soil carbon (C) sequestration is unclear. Here, we describe how losses in plant functional groups (PFGs) affect soil microbial and nematode communities and net ecosystem exchange (NEE) in a 4-year removal experiment conducted on the Mongolian plateau, the world's largest remaining natural grassland. Our results demonstrated that the biomasses or abundances of most components of the two below-ground communities (microbes and nematodes) were negatively affected by PFG loss and were positively related to above-ground plant biomass. The removal of dominant PFGs (perennial bunchgrasses and perennial rhizomatous grasses) reduced the biomass or abundance of below-ground community components while removal of less dominant PFGs (perennial forbs and annuals/biennials) did not change or increased the biomass or abundance of below-ground community components. The biomass-based ratio of fungal to bacterial microbes and the number-based ratio of fungal-feeding to bacterial-feeding nematodes decreased with increasing PFG losses. Variation partitioning analyses showed that the identity of PFGs together with above-ground plant biomass explained most of the total variation in soil microbes and that the identity of PFGs and above-ground plant biomass together with nematode food resources explained most of the total variation in soil nematodes. The increase in NEE with PFG loss was mainly explained by decreases in above-ground plant biomass and the ratio of fungi to bacteria. Synthesis. The shift of below-ground communities from a fungal-based to a bacterial-based energy channel as PFG richness decreases indicates that less diverse grassland ecosystems will have lower nutrient retention and hence be more sensitive to land-use or climate change. The dominant effects of above-ground plant biomass and below-ground communities on NEE indicate that PFG loss resulting from land-use or climate change has the potential to reduce C sequestration in semi-arid grassland soils. These findings suggest that predictive models may need to consider the composition of above-ground and below-ground communities in order to accurately simulate the dynamics of CO2 fluxes in terrestrial ecosystems.}, number={3}, journal={JOURNAL OF ECOLOGY}, author={Chen, Dima and Pan, Qingmin and Bai, Yongfei and Hu, Shuijin and Huang, Jianhui and Wang, Qibing and Naeem, Shahid and Elser, James J. and Wu, Jianguo and Han, Xingguo}, year={2016}, month={May}, pages={734–743} }
 @article{li_hu_polizzotto_chang_shen_ran_yu_2016, title={Fungal biomineralization of montmorillonite and goethite to short-range-ordered minerals}, volume={191}, ISSN={["1872-9533"]}, DOI={10.1016/j.gca.2016.07.009}, abstractNote={Abstract Highly reactive nano-scale minerals, e.g., short-range-ordered minerals (SROs) and other nanoparticles, play an important role in soil carbon (C) retention. Yet, the mechanisms that govern biomineralization from bulk minerals to highly reactive nano-scale minerals remain largely unexplored, which critically hinders our efforts toward managing nano-scale minerals for soil C retention. Here we report the results from a study that explores structural changes during Aspergillus fumigatus Z5 transformation of montmorillonite and goethite to SROs. We examined the morphology and structure of nano-scale minerals, using high-resolution transmission electron microscopy, time-resolved solid-state 27 Al and 29 Si NMR, and Fe K-edge X-ray absorption fine structure spectroscopy combined with two dimensional correlation spectroscopy (2D COS) analysis. Our results showed that after a 48-h cultivation of montmorillonite and goethite with Z5, new biogenic intracellular and extracellular reactive nano-scale minerals with a size of 3–5 nm became abundant. Analysis of 2D COS further suggested that montmorillonite and goethite were the precursors of the dominant biogenic nano-scale minerals. Carbon 1s near edge X-ray absorption fine structure (NEXAFS) spectra and their deconvolution results demonstrated that during fungus Z5 growth, carboxylic C (288.4–289.1 eV) was the dominant organic group, accounting for approximately 34% and 59% in the medium and aggregates, respectively. This result suggested that high percentage of the production of organic acids during the growth of Z5 was the driving factor for structural changes during biomineralization. This is, to the best of our knowledge, the first report of the structural characterization of nano-scale minerals by 2D COS, highlighting its potential to elucidate biomineralization pathways and thus identify the precursors of nano-scale minerals.}, journal={GEOCHIMICA ET COSMOCHIMICA ACTA}, author={Li, Huan and Hu, Shuijin and Polizzotto, Matthew L. and Chang, Xiaoli and Shen, Qirong and Ran, Wei and Yu, Guanghui}, year={2016}, month={Oct}, pages={17–31} }
 @article{li_wang_bai_tao_guo_yang_wang_hu_2016, title={Lead immobilization by geological fluorapatite and fungus Aspergillus niger}, volume={320}, ISSN={["1873-3336"]}, DOI={10.1016/j.jhazmat.2016.08.051}, abstractNote={Phosphate solubilizing fungi have high ability to secrete organic acids. In this study, fungus Aspergillus niger and geological fluorapatite were applied in lead remediation in aqueous solution. Formation and morphology of the lead minerals, e.g., pyromorphite and lead oxalate, were investigated by SEM, XRD, and ATR-IR. The total quantity of organic acids reached the maximum at the sixth day, which improved the concentration of soluble P up to ∼370 mg/L from ∼0.4 mg/L. The organic acids, especially the oxalic acid, enhance the solubility of fluorapatite significantly. The stable fluoropyromorphite [Pb5(PO4)3F] is precipitated with the elevated solubility of fluorapatite in the acidic environment. Furthermore, A. niger grows normally with the presence of lead cations. It is shown that >99% lead cations can be removed from the solution. However, immobilization caused by the precipitation of lead oxalate cannot be ignored if the fungus A. niger was cultured in the Pb solution. This study elucidates the mechanisms of lead immobilization by FAp and A. niger, and sheds its perspective in lead remediation, especially for high Pb concentration solution.}, journal={JOURNAL OF HAZARDOUS MATERIALS}, author={Li, Zhen and Wang, Fuwei and Bai, Tongshuo and Tao, Jinjin and Guo, Jieyun and Yang, Mengying and Wang, Shimei and Hu, Shuijin}, year={2016}, month={Dec}, pages={386–392} }
 @inproceedings{crews_bravo_smith_2016, title={Model development for pzt bimorph actuation employed for micro-air vehicles}, booktitle={Proceedings of the asme conference on smart materials adaptive}, author={Crews, J. and Bravo, N. and Smith, R.}, year={2016} }
 @article{chandrasekaran_kim_krishnamoorthy_walitang_sundaram_joe_selvakumar_hu_oh_sa_2016, title={Mycorrhizal Symbiotic Efficiency on C-3 and C-4 Plants under Salinity Stress - A Meta-Analysis}, volume={7}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2016.01246}, abstractNote={A wide range of C3 and C4 plant species could acclimatize and grow under the impact of salinity stress. Symbiotic relationship between plant roots and arbuscular mycorrhizal fungi (AMF) are widespread and are well known to ameliorate the influence of salinity stress on agro-ecosystem. In the present study, we sought to understand the phenomenon of variability on AMF symbiotic relationship on saline stress amelioration in C3 and C4 plants. Thus, the objective was to compare varied mycorrhizal symbiotic relationship between C3 and C4 plants in saline conditions. To accomplish the above mentioned objective, we conducted a random effects models meta-analysis across 60 published studies. An effect size was calculated as the difference in mycorrhizal responses between the AMF inoculated plants and its corresponding control under saline conditions. Responses were compared between (i) identity of AMF species and AMF inoculation, (ii) identity of host plants (C3 vs. C4) and plant functional groups, (iii) soil texture and level of salinity and (iv) experimental condition (greenhouse vs. field). Results indicate that both C3 and C4 plants under saline condition responded positively to AMF inoculation, thereby overcoming the predicted effects of symbiotic efficiency. Although C3 and C4 plants showed positive effects under low (EC8 ds/m) saline conditions, C3 plants showed significant effects for mycorrhizal inoculation over C4 plants. Among the plant types, C4 annual and perennial plants, C4 herbs and C4 dicot had a significant effect over other counterparts. Between single and mixed AMF inoculants, single inoculants Rhizophagus intraradices had a positive effect on C3 plants whereas Funneliformis mosseae had a positive effect on C4 plants than other species. In all of the observed studies, mycorrhizal inoculation showed positive effects on shoot, root and total biomass, and in nitrogen, phosphorous and potassium (K) uptake. However, it showed negative effects in sodium (Na) uptake in both C3 and C4 plants. This influence, owing to mycorrhizal inoculation, was significantly higher in K uptake in C4 plants. For our analysis, we concluded that AMF-inoculated C4 plants showed more competitive K+ ions uptake than C3 plants.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Chandrasekaran, Murugesan and Kim, Kiyoon and Krishnamoorthy, Ramasamy and Walitang, Denver and Sundaram, Subbiah and Joe, Manoharan M. and Selvakumar, Gopal and Hu, Shuijin and Oh, Sang-Hyon and Sa, Tongmin}, year={2016}, month={Aug} }
 @article{luo_mazer_guo_zhang_weiner_hu_2016, title={Nitrogen:phosphorous supply ratio and allometry in five alpine plant species}, volume={6}, ISSN={2045-7758}, url={http://dx.doi.org/10.1002/ECE3.2587}, DOI={10.1002/ECE3.2587}, abstractNote={In terrestrial ecosystems, atmospheric nitrogen (N) deposition has greatly increased N availability relative to other elements, particularly phosphorus (P). Alterations in the availability of N relative to P can affect plant growth rate and functional traits, as well as resource allocation to above- versus belowground biomass (MA and MB). Biomass allocation among individual plants is broadly size-dependent, and this can often be described as an allometric relationship between MA and MB, as represented by the equation , or log MA = logα + βlog MB. Here, we investigated whether the scaling exponent or regression slope may be affected by the N:P supply ratio. We hypothesized that the regression slope between MA and MB should be steeper under a high N:P supply ratio due to P limitation, and shallower under a low N:P supply ratio due to N limitation. To test these hypotheses, we experimentally altered the levels of N, P, and the N:P supply ratio (from 1.7:1 to 135:1) provided to five alpine species representing two functional groups (grasses and composite forbs) under greenhouse conditions; we then measured the effects of these treatments on plant morphology and tissue content (SLA, leaf area, and leaf and root N/P concentrations) and on the scaling relationship between MA and MB. Unbalanced N:P supply ratios generally negatively affected plant biomass, leaf area, and tissue nutrient concentration in both grasses and composite forbs. High N:P ratios increased tissue N:P ratios in both functional groups, but more in the two composite forbs than in the grasses. The positive regression slopes between log MA and log MB exhibited by plants raised under a N:P supply ratio of 135:1 were significantly steeper than those observed under the N:P ratio of 1.7:1 and 15:1. Synthesis: Plant biomass allocation is highly plastic in response to variation in the N:P supply ratio. Studies of resource allocation of individual plants should focus on the effects of nutrient ratios as well as the availability of individual elements. The two forb species were more sensitive than grasses to unbalanced N:P supplies. To evaluate the adaptive significance of this plasticity, the effects of unbalanced N:P supply ratio on individual lifetime fitness must be measured.}, number={24}, journal={Ecology and Evolution}, publisher={Wiley}, author={Luo, Xi and Mazer, Susan J. and Guo, Hui and Zhang, Nan and Weiner, Jacob and Hu, Shuijin}, year={2016}, month={Nov}, pages={8881–8892} }
 @article{jiang_huang_zhang_zhang_zhang_zheng_deng_zhang_wu_hu_et al._2016, title={Optimizing rice plant photosynthate allocation reduces N2O emissions from paddy fields}, volume={6}, ISSN={["2045-2322"]}, DOI={10.1038/srep29333}, abstractNote={Rice paddies are a major source of anthropogenic nitrous oxide (N2O) emissions, especially under alternate wetting-drying irrigation and high N input. Increasing photosynthate allocation to the grain in rice (Oryza sativa L.) has been identified as an effective strategy of genetic and agronomic innovation for yield enhancement; however, its impacts on N2O emissions are still unknown. We conducted three independent but complementary experiments (variety, mutant study, and spikelet clipping) to examine the impacts of rice plant photosynthate allocation on paddy N2O emissions. The three experiments showed that N2O fluxes were significantly and negatively correlated with the ratio of grain yield to total aboveground biomass, known as the harvest index (HI) in agronomy (P < 0.01). Biomass accumulation and N uptake after anthesis were significantly and positively correlated with HI (P < 0.05). Reducing photosynthate allocation to the grain by spikelet clipping significantly increased white root biomass and soil dissolved organic C and reduced plant N uptake, resulting in high soil denitrification potential (P < 0.05). Our findings demonstrate that optimizing photosynthate allocation to the grain can reduce paddy N2O emissions through decreasing belowground C input and increasing plant N uptake, suggesting the potential for genetic and agronomic efforts to produce more rice with less N2O emissions.}, journal={SCIENTIFIC REPORTS}, author={Jiang, Yu and Huang, Xiaomin and Zhang, Xin and Zhang, Xingyue and Zhang, Yi and Zheng, Chengyan and Deng, Aixing and Zhang, Jun and Wu, Lianhai and Hu, Shuijin and et al.}, year={2016}, month={Jul} }
 @article{chen_li_lan_hu_bai_2016, title={Soil acidification exerts a greater control on soil respiration than soil nitrogen availability in grasslands subjected to long-term nitrogen enrichment}, volume={30}, ISSN={["1365-2435"]}, DOI={10.1111/1365-2435.12525}, abstractNote={Summary
Terrestrial ecosystems worldwide are receiving increasing amounts of biologically reactive nitrogen (N) as a consequence of anthropogenic activities. This intended or unintended fertilization can have a wide-range of impacts on biotic communities and hence on soil respiration.
Reduction in below-ground carbon (C) allocation induced by high N availability has been assumed to be a major mechanism determining the effects of N enrichment on soil respiration. In addition to increasing available N, however, N enrichment causes soil acidification, which may also affect root and microbial activities. The relative importance of increased N availability vs. soil acidification on soil respiration in natural ecosystems experiencing N enrichment is unclear.
We conducted a 12-year N enrichment experiment and a 4-year complementary acid addition experiment in a semi-arid Inner Mongolian grassland. We found that N enrichment had contrasting effects on root and microbial respiration. N enrichment significantly increased root biomass, root N content and specific root respiration, thereby promoting root respiration. In contrast, N enrichment significantly suppressed microbial respiration likely by reducing total microbial biomass and changing the microbial community composition.
The effect on root activities was due to both soil acidity and increased available N, while the effect on microbes primarily stemmed from soil acidity, which was further confirmed by results from the acid addition experiment. Our results indicate that soil acidification exerts a greater control than soil N availability on soil respiration in grasslands experiencing long-term N enrichment.
These findings suggest that N-induced soil acidification should be included in predicting terrestrial ecosystem C balance under future N deposition scenarios.}, number={4}, journal={FUNCTIONAL ECOLOGY}, author={Chen, Dima and Li, Jianjun and Lan, Zhichun and Hu, Shuijin and Bai, Yongfei}, year={2016}, month={Apr}, pages={658–669} }
 @article{jani_grossman_smyth_hu_2016, title={Winter legume cover-crop root decomposition and N release dynamics under disking and roller-crimping termination approaches}, volume={31}, ISSN={1742-1705 1742-1713}, url={http://dx.doi.org/10.1017/S1742170515000113}, DOI={10.1017/S1742170515000113}, abstractNote={Abstract Several approaches can be used to terminate legume cover crops in the spring prior to planting summer crops, but the effect that these methods have on decomposition and nitrogen (N) release dynamics of legume cover-crop roots is poorly understood. The main objectives of this study were to: (i) quantify decomposition and N release of roots from pea ( Pisum sativum ), clover ( Trifolium incarnatum ) and vetch ( Vicia villosa Roth); (ii) determine if roots decompose and release N faster when cover crops are terminated by disking compared with roller-crimping; and (iii) determine if roots decompose and release N faster under higher soil inorganic N levels. Two field experiments were conducted in Goldsboro and Kinston, North Carolina in the summer of 2012. Cover crops at these sites were terminated in spring by disking or roller-crimping and planted to unirrigated corn. Air-dried roots placed in litterbags were buried in their corresponding cover-crop plots and in plots where cover crops had not been grown that had either synthetic N fertilizer added at burial or had no fertilizer addition. Root litterbags were collected over 16 weeks at both sites. Cover-crop plots terminated by disking had up to 117 and 49% higher soil inorganic N than roller-crimped plots in Goldsboro and Kinston, respectively. However, roots did not appear to contribute significantly to these increases, as measured root decomposition and N release was not affected by termination approach at either site. Roots decomposed rapidly at both sites, losing up to 65% of their original biomass within 4 weeks after burial. Root N release was also rapid at both sites, with vetch generally releasing N fastest and clover slowest. It was estimated that cover-crop roots supplied 47–62 and 19–33 kg N ha −1 during the corn cycle in Goldsboro and Kinston, respectively. Our results indicate that under the warm, humid summer conditions of the Southeastern USA, legume cover-crop roots decompose and release N rapidly.}, number={3}, journal={Renewable Agriculture and Food Systems}, publisher={Cambridge University Press (CUP)}, author={Jani, Arun D. and Grossman, Julie and Smyth, Thomas J. and Hu, Shuijin}, year={2016}, pages={214–229} }
 @article{chen_wang_lan_li_xing_hu_bai_2015, title={Biotic community shifts explain the contrasting responses of microbial and root respiration to experimental soil acidification}, volume={90}, ISSN={["0038-0717"]}, DOI={10.1016/j.soilbio.2015.08.009}, abstractNote={Soil respiration is comprised primarily of root and microbial respiration, and accounts for nearly half of the total CO2 efflux from terrestrial ecosystems. Soil acidification resulting from acid deposition significantly affects soil respiration. Yet, the mechanisms that underlie the effects of acidification on soil respiration and its two components remain unclear. We collected data on sources of soil CO2 efflux (microbial and root respiration), above- and belowground biotic communities, and soil properties in a 4-year field experiment with seven levels of acid in a semi-arid Inner Mongolian grassland. Here, we show that soil acidification has contrasting effects on root and microbial respiration in a typical steppe grassland. Soil acidification increases root respiration mainly by an increase in root biomass and a shift to plant species with greater specific root respiration rates. The shift of plant community from perennial bunchgrasses to perennial rhizome grasses was in turn regulated by the decreases in soil base cations and N status. In contrast, soil acidification suppresses microbial respiration by reducing total microbial biomass and enzymatic activities, which appear to result from increases in soil H+ ions and decreases in soil base cations. Our results suggest that shifts in both plant and microbial communities dominate the responses of soil respiration and its components to soil acidification. These results also indicate that carbon cycling models concerned with future climate change should consider soil acidification as well as shifts in biotic communities.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Chen, Dima and Wang, Yang and Lan, Zhichun and Li, Jianjun and Xing, Wen and Hu, Shuijin and Bai, Yongfei}, year={2015}, month={Nov}, pages={139–147} }
 @article{xing_wang_zhou_bloszies_tu_hu_2015, title={EFFECTS OF NH4+- N/NO3--N RATIOS ON PHOTOSYNTHETIC CHARACTERISTICS, DRY MATTER YIELD AND NITRATE CONCENTRATION OF SPINACH}, volume={51}, ISSN={["1469-4441"]}, DOI={10.1017/s0014479714000192}, abstractNote={SUMMARY Most plants prefer nitrate (NO 3 − –N) to ammonium (NH 4 + –N). However, high NO 3 − –N in soil and water systems is a cause of concern for human health and the environment. Replacing NO 3 − –N in plant nutrition regimes with an appropriate amount of NH 4 + –N may alleviate these concerns. The purpose of this study was to evaluate the effects of different NH 4 + –N/NO 3 − –N ratios on chlorophyll content, stomatal conductance, Rubisco activity, net photosynthetic rate, dry matter yield and NO 3 − –N accumulation in spinach grown hydroponically. The NH 4 + –N/NO 3 − –N percentage ratios were 0:100 (control), 25:75, 50:50, 75:25 and 100:0. Chlorophyll a and b, total chlorophyll, stomatal conductance, initial activity and activation state of Rubisco and net photosynthetic rate in spinach leaves were all reduced by increased NH 4 + –N/NO 3 − –N ratios. Significant correlation existed between these measurements. However, no statistical differences in dry matter yield were revealed between the 0:100 and 25:75 treatments. Leaf nitrate concentrations were reduced by 38% at the 25:75 treatment relative to the 0:100 treatment. These findings suggest that lowering the relative proportion of NO 3 − –N in fertilizer could effectively reduce NO 3 − –N contents in leafy vegetables without decreasing their yields.}, number={1}, journal={EXPERIMENTAL AGRICULTURE}, author={Xing, Suzhi and Wang, Jianfei and Zhou, Yi and Bloszies, Sean A. and Tu, Cong and Hu, Shuijin}, year={2015}, month={Jan}, pages={151–160} }
 @article{chen_lan_hu_bai_2015, title={Effects of nitrogen enrichment on belowground communities in grassland: Relative role of soil nitrogen availability vs. soil acidification}, volume={89}, ISSN={["0038-0717"]}, DOI={10.1016/j.soilbio.2015.06.028}, abstractNote={Terrestrial ecosystems worldwide are receiving increasing amounts of biologically reactive nitrogen (N) as a consequence of anthropogenic activities. This intended or unintended fertilization can have a wide range of impacts on the above- and belowground communities. An increase in high N availability has been assumed to be a major mechanism enhancing the abundance of above- and belowground communities. In addition to increasing available N, however, N enrichment causes soil acidification, which may negatively affect above- and belowground communities. The relative importance of increased N availability vs. increased soil acidity for above- and belowground communities in natural ecosystems experiencing N enrichment is unclear. In a 12-year N enrichment experiment in a semi-arid grassland, N enrichment substantially increased both above- and belowground plant biomass mainly via the N availability-induced increase in biomass of perennial rhizome grasses. N enrichment also dramatically suppressed bacterial, fungal, and actinobacteria biomass mainly via the soil acidification pathway (acidification increased concentrations of H+ ions and Al3+ and decreased concentrations of mineral cations). In addition, N enrichment also suppressed bacterial-, fungal-feeding, and omnivorous + carnivorous nematodes mainly via the soil acidification pathway (acidification reduced nematode food resources and reduced concentrations of mineral cations). The positive effects resulting from the increase in belowground carbon allocation (via increase in quantity and quality of plant production) on belowground communities were outweighed by the negative effects resulting from soil acidification, indicating that N enrichment weakens the linkages between aboveground and belowground components of grassland ecosystems. Our results suggest that N enrichment-induced soil acidification should be included in models that predict biota communities and linkages to carbon and nitrogen cycling in terrestrial ecosystems under future scenarios of N deposition.}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Chen, Dima and Lan, Zhichun and Hu, Shuijin and Bai, Yongfei}, year={2015}, month={Oct}, pages={99–108} }
 @article{qiao_liu_hu_compton_greaver_li_2015, title={How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input}, volume={21}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.12802}, abstractNote={Anthropogenic activities, and in particular the use of synthetic nitrogen (N) fertilizer, have doubled global annual reactive N inputs in the past 50–100 years, causing deleterious effects on the environment through increased N leaching and nitrous oxide (N2O) and ammonia (NH3) emissions. Leaching and gaseous losses of N are greatly controlled by the net rate of microbial nitrification. Extensive experiments have been conducted to develop ways to inhibit this process through use of nitrification inhibitors (NI) in combination with fertilizers. Yet, no study has comprehensively assessed how inhibiting nitrification affects both hydrologic and gaseous losses of N and plant nitrogen use efficiency. We synthesized the results of 62 NI field studies and evaluated how NI application altered N cycle and ecosystem services in N-enriched systems. Our results showed that inhibiting nitrification by NI application increased NH3 emission (mean: 20%, 95% confidential interval: 33–67%), but reduced dissolved inorganic N leaching (−48%, −56% to −38%), N2O emission (−44%, −48% to −39%) and NO emission (−24%, −38% to −8%). This amounted to a net reduction of 16.5% in the total N release to the environment. Inhibiting nitrification also increased plant N recovery (58%, 34–93%) and productivity of grain (9%, 6–13%), straw (15%, 12–18%), vegetable (5%, 0–10%) and pasture hay (14%, 8–20%). The cost and benefit analysis showed that the economic benefit of reducing N's environmental impacts offsets the cost of NI application. Applying NI along with N fertilizer could bring additional revenues of $163 ha−1 yr−1 for a maize farm, equivalent to 8.95% increase in revenues. Our findings showed that NIs could create a win-win scenario that reduces the negative impact of N leaching and greenhouse gas production, while increases the agricultural output. However, NI's potential negative impacts, such as increase in NH3 emission and the risk of NI contamination, should be fully considered before large-scale application.}, number={3}, journal={GLOBAL CHANGE BIOLOGY}, author={Qiao, Chunlian and Liu, Lingli and Hu, Shuijin and Compton, Jana E. and Greaver, Tara L. and Li, Quanlin}, year={2015}, month={Mar}, pages={1249–1257} }
 @article{jani_grossman_smyth_hu_2015, title={Influence of soil inorganic nitrogen and root diameter size on legume cover crop root decomposition and nitrogen release}, volume={393}, ISSN={["1573-5036"]}, DOI={10.1007/s11104-015-2473-x}, number={1-2}, journal={PLANT AND SOIL}, author={Jani, Arun D. and Grossman, Julie M. and Smyth, Thomas J. and Hu, Shuijin}, year={2015}, month={Aug}, pages={57–68} }
 @article{chen_cheng_chu_hu_xie_tuvshintogtokh_bai_2015, title={Regional-scale patterns of soil microbes and nematodes across grasslands on the Mongolian plateau: relationships with climate, soil, and plants}, volume={38}, ISSN={["1600-0587"]}, DOI={10.1111/ecog.01226}, abstractNote={Belowground communities exert major controls over the carbon and nitrogen balances of terrestrial ecosystems by regulating decomposition and nutrient availability for plants. Yet little is known about the patterns of belowground communities and their relationships with environmental factors, particularly at the regional scale where multiple environmental gradients co-vary. Here, we describe the patterns of belowground communities (microbes and nematodes) and their relationships with environmental factors based on two parallel studies: a field survey with two regional-scale transects across the Mongolia plateau and a water-addition experiment in a typical steppe. In the field survey, soils and plants were collected across two large-scale transects (a 2000-km east–west transect and a 900-km south–north transect). At the regional-scale, the variations in soil microbes (e.g. bacterial PLFA, fungal PLFA, and F/B ratio) were mainly explained by precipitation and soil factors. In contrast, the variation in soil nematodes (e.g. density of trophic groups and the bacterial-feeding/fungalfeeding nematode ratio) were primarily explained by precipitation. These variations of microbe or nematode variables explained by environmental factors at regional scale were derived from different vegetation types. Along the gradient from nutrient-poor to nutrient-rich vegetation types, the total variation in soil microbes explained by precipitation increased and that explained by plant and soil decreased, while the opposite was true for soil nematodes. Experimental water addition, which increased rainfall by 30% during the growing season, increased biomass or density of belowground communities, with the nematodes being more responsive than the microbes. The different responses of soil microbial and nematode communities to environmental gradients at the regional scale likely reflect their different adaptations to climate, soil nutrients, and plants. Our findings suggest that the soil nematode and microbial communities are strongly controlled by bottom-up effects of precipitation alone or in combination with soil conditions.}, number={6}, journal={ECOGRAPHY}, author={Chen, Dima and Cheng, Junhui and Chu, Pengfei and Hu, Shuijin and Xie, Yichun and Tuvshintogtokh, Indree and Bai, Yongfei}, year={2015}, month={Jun}, pages={622–631} }
 @article{chandrasekaran_boughattas_hu_oh_sa_2014, title={A meta-analysis of arbuscular mycorrhizal effects on plants grown under salt stress}, volume={24}, ISSN={["1432-1890"]}, DOI={10.1007/s00572-014-0582-7}, number={8}, journal={MYCORRHIZA}, author={Chandrasekaran, Murugesan and Boughattas, Sonia and Hu, Shuijin and Oh, Sang-Hyon and Sa, Tongmin}, year={2014}, month={Nov}, pages={611–625} }
 @article{yuan_tang_leng_hu_yong_chen_2014, title={An Invasive Plant Promotes Its Arbuscular Mycorrhizal Symbioses and Competitiveness through Its Secondary Metabolites: Indirect Evidence from Activated Carbon}, volume={9}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0097163}, abstractNote={Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC), a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM) symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1-3) with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC) of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts.}, number={5}, journal={PLOS ONE}, author={Yuan, Yongge and Tang, Jianjun and Leng, Dong and Hu, Shuijin and Yong, Jean W. H. and Chen, Xin}, year={2014}, month={May} }
 @article{lee_tu_chen_hu_2014, title={Arbuscular mycorrhizal fungi enhance P uptake and alter plant morphology in the invasive plant Microstegium vimineum}, volume={16}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-013-0562-4}, number={5}, journal={BIOLOGICAL INVASIONS}, author={Lee, Marissa R. and Tu, Cong and Chen, Xin and Hu, Shuijin}, year={2014}, month={May}, pages={1083–1093} }
 @article{liu_jiang_hu_li_liu_wan_2014, title={Decoupling of soil microbes and plants with increasing anthropogenic nitrogen inputs in a temperate steppe}, volume={72}, DOI={10.1016/j.soilbio.2014.01.022}, abstractNote={Plant growth and soil microbial activity are intrinsically correlated. Numerous evidence shows that nitrogen (N) deposition can greatly alter both processes. However, it is unknown whether such changes caused by N deposition can create new dynamics between plants and soil microbes. This study was conducted with an attempt to examine the plant–microbe relationship along an N addition gradient. Eight levels of N addition (0, 1, 2, 4, 8, 16, 32, 64 g N m−2) were applied annually in a temperate steppe in northern China since 2003. Plant and soil samples were collected from 2005 to 2007. We found that N addition acidified soil significantly. Both plant aboveground biomass and dissolved organic carbon (DOC) increased with increasing N input. However, soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and (soil) microbial respiration showed nonlinear responses to N input. Low levels of N inputs stimulated MBC, MBN and microbial respiration, whereas high levels of N input suppressed them. Although MBC and MBN were both positively correlated with aboveground biomass at each level of N treatments, the dependence of such biomass on MBC and MBN declined with the increase in N addition, as indicated by the exponential decreases in the regression coefficients. The weakened linkage between aboveground biomass and MBC was mostly attributed to soil acidification. The decrease in soil pH caused by elevated N inputs reduced soil microbial activities, but not plant growth. Overall, our results revealed a trend of shifting plant–microbe relationship from coupling to decoupling with the increase of N input. The divergent responses of plants and soil microbial activities under intensified N addition could have consequent impacts on ecosystem function and services.}, journal={Soil Biology & Biochemistry}, author={Liu, W. X. and Jiang, L. and Hu, Shuijin and Li, L. H. and Liu, L. L. and Wan, S. Q.}, year={2014}, pages={116–122} }
 @article{zerpa_allen_mclaughlin_phelan_campbell_hu_2014, title={Postharvest forest floor manipulation effects on nutrient dynamics in a loblolly pine (Pinus taeda) plantation}, volume={44}, ISSN={["1208-6037"]}, DOI={10.1139/cjfr-2013-0536}, abstractNote={The synchronization of nutrient release and demand in early stand establishment is important to maximizing resource use in forest plantations. We explored the impacts of forest floor manipulations on the dynamics of forest floor and mineral soil nutrient pools in a Pinus taeda L. plantation in North Carolina prior to and during 2 years following harvest and replanting. We present a novel method to estimate forest floor decomposition that avoids the exclusion of large detritivores. Decomposition and nutrient release rates from the forest floor were higher than rates typically observed in older stands (averaging 81% mass loss and 75% N loss across treatments over the 2-year period), highlighting the potential importance of the forest floor nutrient pool in early stand nutrition. Doubling the forest floor increased available C, N, and P pools in the mineral soil 46%, 47%, and 49%, respectively. Incorporating the forest floor into mineral soil through mixing had only transient positive effects on nutrient pools. Across treatments, an expected postharvest flush of soil available N was observed; however, removing the forest floor caused an earlier flush of available N in comparison with the control treatment, and doubling the forest floor caused a year delay in maximum N availability, better synchronizing the site’s available N with stand demand.}, number={9}, journal={CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE}, author={Zerpa, Jose L. and Allen, H. Lee and McLaughlin, Blair C. and Phelan, Jennifer and Campbell, Robert G. and Hu, Shuijin}, year={2014}, month={Sep}, pages={1058–1067} }
 @article{cheng_booker_burkey_tu_shew_rufty_fiscus_deforest_hu_2014, title={SOIL MICROBIAL RESPONSES TO ELEVATED CO2 AND O-3 IN A NITROGEN-AGGRADING AGROECOSYSTEM}, volume={6}, ISBN={["978-1-77188-021-3"]}, DOI={10.1371/journal.pone.0021377}, abstractNote={Climate change factors such as elevated atmospheric carbon dioxide (CO2) and ozone (O3) can exert significant impacts on soil microbes and the ecosystem level processes they mediate. However, the underlying mechanisms by which soil microbes respond to these environmental changes remain poorly understood. The prevailing hypothesis, which states that CO2- or O3-induced changes in carbon (C) availability dominate microbial responses, is primarily based on results from nitrogen (N)-limiting forests and grasslands. It remains largely unexplored how soil microbes respond to elevated CO2 and O3 in N-rich or N-aggrading systems, which severely hinders our ability to predict the long-term soil C dynamics in agroecosystems. Using a long-term field study conducted in a no-till wheat-soybean rotation system with open-top chambers, we showed that elevated CO2 but not O3 had a potent influence on soil microbes. Elevated CO2 (1.5×ambient) significantly increased, while O3 (1.4×ambient) reduced, aboveground (and presumably belowground) plant residue C and N inputs to soil. However, only elevated CO2 significantly affected soil microbial biomass, activities (namely heterotrophic respiration) and community composition. The enhancement of microbial biomass and activities by elevated CO2 largely occurred in the third and fourth years of the experiment and coincided with increased soil N availability, likely due to CO2-stimulation of symbiotic N2 fixation in soybean. Fungal biomass and the fungi∶bacteria ratio decreased under both ambient and elevated CO2 by the third year and also coincided with increased soil N availability; but they were significantly higher under elevated than ambient CO2. These results suggest that more attention should be directed towards assessing the impact of N availability on microbial activities and decomposition in projections of soil organic C balance in N-rich systems under future CO2 scenarios.}, number={6}, journal={CARBON CAPTURE AND STORAGE: CO2 MANAGEMENT TECHNOLOGIES}, author={Cheng, Lei and Booker, Fitzgerald L. and Burkey, Kent O. and Tu, Cong and Shew, H. David and Rufty, Thomas W. and Fiscus, Edwin L. and Deforest, Jared L. and Hu, Shuijin}, year={2014}, pages={277–307} }
 @article{yi_wen-xia_tu_washburn_lei_hu_2014, title={Soil Carbon, Nitrogen and Microbial Dynamics of Pasturelands: Impacts of Grazing Intensity and Planting Systems}, volume={24}, ISSN={["2210-5107"]}, DOI={10.1016/s1002-0160(14)60027-8}, abstractNote={Management intensity critically influences the productivity and sustainability of pasture systems through modifying soil microbes, and soil carbon (C) and nutrient dynamics; however, such effects are not well understood yet in the southeastern USA. We examined the effects of grazing intensity and grass planting system on soil C and nitrogen (N) dynamics, and microbial biomass and respiration in a long-term field experiment in Goldsboro, North Carolina, USA. A split-plot experiment was initiated in 2003 on a highly sandy soil under treatments of two grass planting systems (ryegrass rotation with sorghum-sudangrass hybrid and ryegrass seeding into a perennial bermudagrass stand) at low and high grazing densities. After 4 years of continuous treatments, soil total C and N contents across the 0–30 cm soil profile were 24.7% and 17.5% higher at the high than at the low grazing intensity, likely through promoting plant productivity and C allocation belowground as well as fecal and urinary inputs. Grass planting system effects were significant only at the low grazing intensity, with soil C, N, and microbial biomass and respiration in the top 10 cm being higher under the ryegrass/bermudagrass than under the ryegrass/sorghum-sudangrass hybrid planting systems. These results suggest that effective management could mitigate potential adverse effects of high grazing intensities on soil properties and facilitate sustainability of pastureland.}, number={3}, journal={PEDOSPHERE}, author={Yi, Wang and Wen-Xia, Duan and Tu, C. and Washburn, S. and Lei, Cheng and Hu, S.}, year={2014}, month={Jun}, pages={408–416} }
 @article{larsen_grossman_edgell_hoyt_osmond_hu_2014, title={Soil biological properties, soil losses and corn yield in long-term organic and conventional farming systems}, volume={139}, ISSN={["1879-3444"]}, DOI={10.1016/j.still.2014.02.002}, abstractNote={Abstract Topsoil losses through surface runoff have severe implications for farmers, as well as surrounding ecosystems and waterbodies. However, integrating management systems that enhance soil organic matter (SOM) can stabilize the soil surface from erosion. Little is known about how differences in both tillage and cropping system management affect carbon and subsequent sediment losses in horticultural fields, particularly in the humid climate of the southeast. Research was conducted in the Appalachian Mountains in Mills River, NC on a fine-sandy loam Acrisol from 2010 to 2012 on long-term plots established in 1994. Project objectives included to: (1) quantify labile and total organic matter based on tillage and cropping system practices, (2) determine if relationships exist between SOC ad sediment losses, and (3) determine long-term management and tillage impacts on total organic matter lost via runoff. We hypothesized that organic management and reduced tillage would lead to increased soil carbon, which subsequently reduce losses as soil is stabilized. Organic no tillage and conventional till treatments contained on average 14.34 and 6.80 g kg −1 total carbon (TC) respectively, with the organic no till treatments containing twice the quantity of TC and light fraction particulate organic matter (LPOM) in the upper 15 cm as compared with the conventionally tilled treatments, and four times the quantity of microbial biomass carbon (MBC). LPOM and HPOM, the heavier fraction of POM, did not differ in the organic till and conventional no till treatments.Data support our hypothesis that organic production in combination with no tillage increases C pools (both total and labile) as compared with tilled conventional plots. However, organic no till treatments produced sweet corn ( Zea mays var. saccharata ) yields less than 50% of that of conventional treatments, attributed to weed competition and lack of available N. No tillage treatments lost two to four times less soil C via surface runoff than tilled systems. Additionally, we found that as total soil C increased, suspended solids lost through surface runoff decreased. Overall, our results indicate tillage to be an important factor in enhancing soil C and decreasing soil loss through surface runoff.}, journal={SOIL & TILLAGE RESEARCH}, author={Larsen, Erika and Grossman, Julie and Edgell, Joshua and Hoyt, Greg and Osmond, Deanna and Hu, Shuijin}, year={2014}, month={Jun}, pages={37–45} }
 @article{cheng_booker_burkey_tu_shew_rufty_fiscus_deforest_hu_2014, title={Soil microbial responses to elevated CO2 and O-3 in a nitrogen-aggrading agroecosystem}, DOI={10.1201/b16845-14}, journal={Carbon Capture and Storage: CO2 Management Technologies}, author={Cheng, L. and Booker, F. L. and Burkey, K. O. and Tu, C. and Shew, H. D. and Rufty, T. W. and Fiscus, E. L. and Deforest, J. L. and Hu, Shuijin}, year={2014}, pages={277–307} }
 @article{rua_umbanhowar_hu_burkey_mitchell_2013, title={Elevated CO2 spurs reciprocal positive effects between a plant virus and an arbuscular mycorrhizal fungus}, volume={199}, ISSN={["1469-8137"]}, DOI={10.1111/nph.12273}, abstractNote={Plants form ubiquitous associations with diverse microbes. These interactions range from parasitism to mutualism, depending partly on resource supplies that are being altered by global change. While many studies have considered the separate effects of pathogens and mutualists on their hosts, few studies have investigated interactions among microbial mutualists and pathogens in the context of global change. Using two wild grass species as model hosts, we grew individual plants under ambient or elevated CO(2), and ambient or increased soil phosphorus (P) supply. Additionally, individuals were grown with or without arbuscular mycorrhizal inoculum, and after 2 wk, plants were inoculated or mock-inoculated with a phloem-restricted virus. Under elevated CO(2), mycorrhizal association increased the titer of virus infections, and virus infection reciprocally increased the colonization of roots by mycorrhizal fungi. Additionally, virus infection decreased plant allocation to root biomass, increased leaf P, and modulated effects of CO(2) and P addition on mycorrhizal root colonization. These results indicate that plant mutualists and pathogens can alter each other's success, and predict that these interactions will respond to increased resource availability and elevated CO(2). Together, our findings highlight the importance of interactions among multiple microorganisms for plant performance under global change.}, number={2}, journal={NEW PHYTOLOGIST}, author={Rua, Megan A. and Umbanhowar, James and Hu, Shuijin and Burkey, Kent O. and Mitchell, Charles E.}, year={2013}, month={Jul}, pages={541–549} }
 @article{yuan_wang_zhang_tang_tu_hu_yong_chen_2013, title={Enhanced allelopathy and competitive ability of invasive plant Solidago canadensis in its introduced range}, volume={6}, ISSN={["1752-993X"]}, DOI={10.1093/jpe/rts033}, abstractNote={Why invasive plants are more competitive in their introduced range than native range is still an unanswered question in plant invasion ecology. Here, we used the model invasive plant Solidago canadensis to test a hypothesis that enhanced production of allelopathic compounds results in greater competitive ability of invasive plants in the invaded range rather than in the native range. We also examined the degree to which the allelopathy contributes increased competitive ability of S. canadensis in the invaded range. We compared allelochemical production by S. canadensis growing in its native area (the USA) and invaded area (China) and also by populations that were collected from the two countries and grown together in a ‘common garden’ greenhouse experiment. We also tested the allelopathic effects of S. canadensis collected from either the USA or China on the germination of Kummerowia striata (a native plant in China). Finally, we conducted a common garden, greenhouse experiment in which K. striata was grown in monoculture or with S. canadensis from the USA or China to test the effects of allelopathy on plant–plant competition with suitable controls such as adding activated carbon to the soil to absorb the allelochemicals and thereby eliminating any corresponding allopathic effects. Allelochemical contents (total phenolics, total flavones and total saponins) and allelopathic effects were greater in S. canadensis sampled from China than those from the USA as demonstrated in a field survey and a common garden experiment. Inhibition of K. striata germination using S. canadensis extracts or previously grown in soil was greater using samples from China than from the USA. The competitive ability of S. canadensis against K. striata was also greater for plants originating from China than those from the USA. Allelopathy could explain about 46% of the difference. These findings demonstrated that S. canadensis has evolved to be more allelopathic and competitive in the introduced range and that allelopathy significantly contributes to increased competitiveness for this invasive species.}, number={3}, journal={JOURNAL OF PLANT ECOLOGY}, author={Yuan, Yongge and Wang, Bing and Zhang, Shanshan and Tang, Jianjun and Tu, Cong and Hu, Shuijin and Yong, Jean W. H. and Chen, Xin}, year={2013}, month={Jun}, pages={253–263} }
 @article{xie_xu_liu_liu_zhu_tu_amonette_cadisch_yong_hu_2013, title={Impact of biochar application on nitrogen nutrition of rice, greenhouse-gas emissions and soil organic carbon dynamics in two paddy soils of China}, volume={370}, ISSN={["1573-5036"]}, DOI={10.1007/s11104-013-1636-x}, number={1-2}, journal={PLANT AND SOIL}, author={Xie, Zubin and Xu, Yanping and Liu, Gang and Liu, Qi and Zhu, Jianguo and Tu, Cong and Amonette, James E. and Cadisch, Georg and Yong, Jean W. H. and Hu, Shuijin}, year={2013}, month={Sep}, pages={527–540} }
 @article{cheng_booker_tu_burkey_zhou_shew_rufty_hu_2012, title={Arbuscular Mycorrhizal Fungi Increase Organic Carbon Decomposition Under Elevated CO2}, volume={337}, ISSN={["1095-9203"]}, DOI={10.1126/science.1224304}, abstractNote={A Fungal Culprit to Carbon Loss In some ecosystems, such as in the layer of soil containing plant roots, fungi, and bacteria, increased levels of CO 2 should stimulate more efficient aboveground photosynthesis, which in turn should promote increased sequestration of organic carbon in soil through the protective action of arbuscular mycorrhizal fungi. However, in a series of field and microcosm experiments performed under elevated levels of CO 2 thought to be consistent with future emissions scenarios, Cheng et al. (p. 1084 ; see the Perspective by Kowalchuk ) observed that these fungi actually promote degradation of soil organic carbon, releasing more CO 2 in the process.}, number={6098}, journal={SCIENCE}, author={Cheng, Lei and Booker, Fitzgerald L. and Tu, Cong and Burkey, Kent O. and Zhou, Lishi and Shew, H. David and Rufty, Thomas W. and Hu, Shuijin}, year={2012}, month={Aug}, pages={1084–1087} }
 @article{schroeder-moreno_greaver_wang_hu_rufty_2012, title={Mycorrhizal-mediated nitrogen acquisition in switchgrass under elevated temperatures and N enrichment}, volume={4}, ISSN={["1757-1707"]}, DOI={10.1111/j.1757-1707.2011.01128.x}, abstractNote={Arbuscular mycorrhizal fungi (AMF) can perform key roles in ecosystem functioning through improving host nutrient acquisition. Nitrogen (N) is an essential nutrient for plant growth, however, anthropogenic N loading (e.g. crop fertilization and deposition from combustion sources) is increasing so that N now threatens ecosystem sustainability around the world by causing terrestrial and aquatic eutrophication and acidification. It is important to better understand the capacity of AMF to directly uptake N from soils and transfer it to host plants because this process may increase N recycling and retention within ecosystems. In addition to understanding the role of AMF in the N cycle in the present day it is important to understand how AMF function may change as global change proceeds. Currently the net effects of N enrichment and elevated temperature predicted with global change on AMF are unknown. In this study, we examined the effects of N enrichment by simulated N-deposition loading, elevated temperatures expected by future global changes and their interactions on growth and AMF-mediated N acquisition of switchgrass (Panicum virgatum var. Alamo), an important species for biofuel production. Switchgrass plants were grown in microcosm units that divided mycorrhizal roots from AMF hyphae and organic residues enriched with 15N by compartments separated by an air gap to reduce N diffusion. While AMF did not enhance switchgrass biomass, mycorrhizas significantly increased 15N in shoots and total shoot N. Neither N enrichment nor elevated temperatures influenced this mycorrhizal-mediated N uptake and transfer. Results from this study can aid in developing sustainable bioethanol and switchgrass production practices that are less reliant on synthetic fertilizers and more dependent on internal N recycling from AMF.}, number={3}, journal={GLOBAL CHANGE BIOLOGY BIOENERGY}, author={Schroeder-Moreno, Michelle S. and Greaver, Tara L. and Wang, Shuxin and Hu, Shujin and Rufty, Thomas W.}, year={2012}, month={May}, pages={266–276} }
 @article{tu_wang_duan_hertl_tradway_brandenburg_lee_snell_hu_2011, title={Effects of fungicides and insecticides on feeding behavior and community dynamics of earthworms: Implications for casting control in turfgrass systems}, volume={47}, ISSN={0929-1393}, url={http://dx.doi.org/10.1016/j.apsoil.2010.11.002}, DOI={10.1016/j.apsoil.2010.11.002}, abstractNote={Earthworms play important roles in sustaining turfgrass systems through enhancing soil aeration, water filtration, and thatch mixing and decomposition. However, high surface activities of earthworms can lead to uneven playing surfaces, soil erosion and new niches favorable to weed invasion in the playing area of a golf course. Shifts from highly toxic and persistent to less toxic and easily degradable pesticides have been suggested to be largely responsible for high earthworm activities observed in turf systems worldwide. In this study, we examined the impact of fungicides and insecticides on earthworm behavior in controlled environments and on the dynamics of earthworm community in the field. Single application of insecticides Sevin (carbaryl) and Merit (imidacloprid) at the manufactures’ suggested doses significantly inhibited earthworm feeding activity for at least three weeks without leading to any earthworm death. Fungicides did not show significant toxicity to earthworms when applied only once, but their toxicities increased as application frequency increased. Consecutive weekly applications of Sevin, Merit and T-methyl for four times led to earthworm mortality of 35, 45 and 80%, respectively. In the field, six consecutive weekly applications of T-methyl and Sevin significantly reduced the abundance and biomass of earthworms with suppressive effects lasting for at least 6 weeks after the chemical application was terminated. Taken together, these findings suggest that the surface activities of earthworms in turfgrass systems may be managed through moderate application of pesticides at peak periods of earthworm activities.}, number={1}, journal={Applied Soil Ecology}, publisher={Elsevier BV}, author={Tu, Cong and Wang, Yi and Duan, Wenxia and Hertl, Peter and Tradway, Lane and Brandenburg, Rick and Lee, David and Snell, Mark and Hu, Shuijin}, year={2011}, month={Jan}, pages={31–36} }
 @article{wang_tu_cheng_li_gentry_hoyt_zhang_hu_2011, title={Long-term impact of farming practices on soil organic carbon and nitrogen pools and microbial biomass and activity}, volume={117}, ISSN={["0167-1987"]}, DOI={10.1016/j.still.2011.08.002}, abstractNote={Conventional agriculture with intensive tillage and high inputs of synthetic chemicals has critically depleted the soil C pools. Alternative practices such as no-tillage and organic inputs have been shown to increase soil C content. However, the long-term impact of these practices on soil C pools was not fully understood under humid and warm climate conditions such as the southeast USA. We hypothesized that a combination of sustainable production practices will result in greater microbial biomass and activity and soil organic C than any individual practice. To test this hypothesis, we conducted a long-term experiment examining how different farming practices affect soil C and N pools and microbial biomass and activities in a fine-sandy loam (FAO: Acrisol) in the southern Appalachian mountains of North Carolina, USA. The experiment was a randomized complete design with four replications. Six management treatments, i.e., tillage with no chemical or organic inputs (Control, TN), tillage with chemical inputs (TC), tillage with organic inputs (TO), no-tillage with chemical inputs (NC), no-tillage with organic inputs (NO), and fescue grasses (FG), were designed. Organic C and N pools and microbial properties in 0–15 cm soils were markedly different after 15 years of continuous treatments. Both no tillage and organic inputs significantly promoted soil microbial biomass by 63–139% and 54–126%; also microbial activity increased by 88–158% and 52–117%, respectively. Corresponding increases of soil organic C by 83–104% and 19–32%, and soil organic N by 77–94% and 20–32% were measured. The combination of no tillage and organic management increased soil organic C by 140% over the conventional tillage control, leading to a soil C content comparable to an un-disturbed grassland control. No tillage reduced the proportion of organic C in the light fraction with d < 1.0 g cm−3 (from 1.53–3.39% to 0.80–1.09%), and increased the very heavy fraction with d > 1.6 g cm−3 (from 95% to 98%). Organic inputs, however, had little impact on C distribution among different density fractions of the soil except light fraction in tillage treatment. Over all, no-tillage practices exerted greater influence on microbial biomass levels and activity and soil organic C levels and fractionations than organic inputs. Our results support the hypothesis and indicate that management decisions including reducing tillage and increasing organic C inputs can enhance transformation of soil organic C from the labile into stable pools, promote soil C accumulation, improve soil fertility and while mitigate atmospheric CO2 rise.}, journal={SOIL & TILLAGE RESEARCH}, author={Wang, Yi and Tu, Cong and Cheng, Lei and Li, Chunyue and Gentry, Laura F. and Hoyt, Greg D. and Zhang, Xingchang and Hu, Shuijin}, year={2011}, month={Dec}, pages={8–16} }
 @article{cheng_zhu_chen_zheng_oh_rufty_richter_hu_2010, title={Atmospheric CO2 enrichment facilitates cation release from soil}, volume={13}, ISSN={["1461-0248"]}, DOI={10.1111/j.1461-0248.2009.01421.x}, abstractNote={Ecology Letters (2010) 13: 284–291 Atmospheric CO2 enrichment generally stimulates plant photosynthesis and nutrient uptake, modifying the local and global cycling of bioactive elements. Although nutrient cations affect the long-term productivity and carbon balance of terrestrial ecosystems, little is known about the effect of CO2 enrichment on cation availability in soil. In this study, we present evidence for a novel mechanism of CO2-enhancement of cation release from soil in rice agricultural systems. Elevated CO2 increased organic C allocation belowground and net H+ excretion from roots, and stimulated root and microbial respiration, reducing soil redox potential and increasing Fe2+ and Mn2+ in soil solutions. Increased H+, Fe2+, and Mn2+ promoted Ca2+ and Mg2+ release from soil cation exchange sites. These results indicate that over the short term, elevated CO2 may stimulate cation release from soil and enhance plant growth. Over the long-term, however, CO2-induced cation release may facilitate cation losses and soil acidification, negatively feeding back to the productivity of terrestrial ecosystems.}, number={3}, journal={ECOLOGY LETTERS}, author={Cheng, L. and Zhu, J. and Chen, G. and Zheng, X. and Oh, N. -H. and Rufty, T. W. and Richter, D. deB and Hu, S.}, year={2010}, month={Mar}, pages={284–291} }
 @article{zhang_jin_zhu_tang_hu_zhou_chen_2010, title={Baicalin Released from Scutellaria baicalensis Induces Autotoxicity and Promotes Soilborn Pathogens}, volume={36}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-010-9760-z}, number={3}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Zhang, Shanshan and Jin, Yili and Zhu, Wenjie and Tang, Jianjun and Hu, Shuijin and Zhou, Tongshui and Chen, Xin}, year={2010}, month={Mar}, pages={329–338} }
 @article{zhang_yang_tang_yang_hu_chen_2010, title={Positive Feedback between Mycorrhizal Fungi and Plants Influences Plant Invasion Success and Resistance to Invasion}, volume={5}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0012380}, abstractNote={Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.}, number={8}, journal={PLOS ONE}, author={Zhang, Qian and Yang, Ruyi and Tang, Jianjun and Yang, Haishui and Hu, Shuijin and Chen, Xin}, year={2010}, month={Aug} }
 @article{sydorovych_raczkowski_wossink_mueller_creamer_hu_bell_tu_2009, title={A technique for assessing environmental impact risks of agricultural systems}, volume={24}, ISSN={["1742-1713"]}, DOI={10.1017/S174217050999010X}, abstractNote={Abstract Conventional agriculture often aims to achieve high returns without allowing for sustainable natural resource management. To prevent environmental degradation, agricultural systems must be assessed and environmental standards need to be developed. This study used a multi-factor approach to assess the potential environmental impact risk of six diverse systems: five production systems and a successional system or abandoned agronomic field. Assessment factors were soil quality status, amount of pesticide and fertilizer applied and tillage intensity. The assessment identified the best management practices (BMP)–conventional tillage system as a high-risk system mostly because of extensive tillage. The certified organic system was also extensively tilled and was characterized by P build-up in the soil, but performed well based on other assessment factors. Conversely, the BMP–no tillage and the crop–animal integrated system were characterized as low risk mainly because of reduced tillage. The paper discusses assessment strengths and weaknesses, ways to improve indicators used, and the need for additional indicators. We concluded that with further development the technique will become a resourceful tool to promote agricultural sustainability and environmental stewardship and assist policy-making processes.}, number={3}, journal={RENEWABLE AGRICULTURE AND FOOD SYSTEMS}, author={Sydorovych, Olha and Raczkowski, Charles W. and Wossink, Ada and Mueller, J. Paul and Creamer, Nancy G. and Hu, Shuijin and Bell, Melissa and Tu, Cong}, year={2009}, month={Sep}, pages={234–243} }
 @article{tu_booker_burkey_hu_2009, title={Elevated Atmospheric Carbon Dioxide and O-3 Differentially Alter Nitrogen Acquisition in Peanut}, volume={49}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2008.10.0603}, abstractNote={ABSTRACT Elevated atmospheric CO 2 and ozone (O 3 ) may affect productivity of legumes in part by altering symbiotic N 2 fixation. To investigate this possibility, measurements of plant biomass, N levels and natural 15 N abundance (δ 15 N) were used to examine the effects of elevated CO 2 and O 3 on N acquisition in field‐grown peanut ( Arachis hypogaea L.) using open‐top chambers. Seasonal 12‐h daily average CO 2 treatment concentrations were 376, 550, and 730 μmol mol −1 Carbon dioxide treatments were applied in reciprocal combinations with seasonal 12‐h daily average O 3 concentrations of 21, 49, and 79 nmol mol −1 At mid‐vegetative growth, elevated CO 2 significantly reduced leaf N concentrations by up to 44%, but not δ 15 N values. Elevated O 3 did not significantly affect N concentrations or δ 15 N values. At harvest, plant N concentrations were similar among treatments except for a 14% reduction in the highest‐level CO 2 –O 3 treatment. Plant N accumulation varied in proportion with treatment effects on biomass production, which was increased with elevated CO 2 when averaged over the O 3 treatments and suppressed by high‐level O 3 at ambient CO 2 Elevated CO 2 reduced plant δ 15 N values in low‐ and mid‐level O 3 treatments while mid‐ and high‐level O 3 increased them at ambient CO 2 The changes in δ 15 N values suggested that N 2 fixation activity was stimulated with elevated CO 2 and inhibited by elevated O 3 Elevated CO 2 ameliorated detrimental O 3 effects to varying extents depending on the concentrations of the two gases. These results indicated that interactions between CO 2 and O 3 on plant physiology can alter N acquisition processes, with impacts on peanut productivity likely dependent in part on these changes.}, number={5}, journal={CROP SCIENCE}, author={Tu, Cong and Booker, Fitzgerald L. and Burkey, Kent O. and Hu, Shuijin}, year={2009}, pages={1827–1836} }
 @article{liu_king_booker_giardina_allen_hu_2009, title={Enhanced litter input rather than changes in litter chemistry drive soil carbon and nitrogen cycles under elevated CO2: a microcosm study}, volume={15}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2008.01747.x}, abstractNote={Elevated CO2 has been shown to stimulate plant productivity and change litter chemistry. These changes in substrate availability may then alter soil microbial processes and possibly lead to feedback effects on N availability. However, the strength of this feedback, and even its direction, remains unknown. Further, uncertainty remains whether sustained increases in net primary productivity will lead to increased long-term C storage in soil. To examine how changes in litter chemistry and productivity under elevated CO2 influence microbial activity and soil C formation, we conducted a 230-day microcosm incubation with five levels of litter addition rate that represented 0, 0.5, 1.0, 1.4 and 1.8 × litterfall rates observed in the field for aspen stand growing under control treatments at the Aspen FACE experiment in Rhinelander, WI, USA. Litter and soil samples were collected from the corresponding field control and elevated CO2 treatment after trees were exposed to elevated CO2 (560 ppm) for 7 years. We found that small decreases in litter [N] under elevated CO2 had minor effects on microbial biomass carbon, microbial biomass nitrogen and dissolved inorganic nitrogen. Increasing litter addition rates resulted in linear increase in total C and new C (C from added litter) that accumulated in whole soil as well as in the high density soil fraction (HDF), despite higher cumulative C loss by respiration. Total N retained in whole soil and in HDF also increased with litter addition rate as did accumulation of new C per unit of accumulated N. Based on our microcosm comparisons and regression models, we expected that enhanced C inputs rather than changes in litter chemistry would be the dominant factor controlling soil C levels and turnover at the current level of litter production rate (230 g C m−2 yr−1 under ambient CO2). However, our analysis also suggests that the effects of changes in biochemistry caused by elevated CO2 could become significant at a higher level of litter production rate, with a trend of decreasing total C in HDF, new C in whole soil, as well as total N in whole soil and HDF.}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Liu, Lingli and King, John S. and Booker, Fitzgerald L. and Giardina, Christian P. and Allen, H. Lee and Hu, Shuijin}, year={2009}, month={Feb}, pages={441–453} }
 @article{tang_xu_chen_hu_2009, title={Interaction between C-4 barnyard grass and C-3 upland rice under elevated CO2: Impact of mycorrhizae}, volume={35}, ISSN={["1873-6238"]}, DOI={10.1016/j.actao.2008.10.005}, abstractNote={Abstract Atmospheric CO 2 enrichment may impact arbuscular mycorrhizae (AM) development and function, which could have subsequent effects on host plant species interactions by differentially affecting plant nutrient acquisition. However, direct evidence illustrating this scenario is limited. We examined how elevated CO 2 affects plant growth and whether mycorrhizae mediate interactions between C 4 barnyard grass ( Echinochloa crusgalli (L.) Beauv.) and C 3 upland rice ( Oryza sativa L.) in a low nutrient soil. The monocultures and combinations with or without mycorrhizal inoculation were grown at ambient (400 ± 20 μmol mol −1 ) and elevated CO 2 (700 ± 20 μmol mol −1 ) levels. The 15 N isotope tracer was introduced to quantify the mycorrhizally mediated N acquisition of plants. Elevated CO 2 stimulated the growth of C 3 upland rice but not that of C 4 barnyard grass under monoculture. Elevated CO 2 also increased mycorrhizal colonization of C 4 barnyard grass but did not affect mycorrhizal colonization of C 3 upland rice. Mycorrhizal inoculation increased the shoot biomass ratio of C 4 barnyard grass to C 3 upland rice under both CO 2 concentrations but had a greater impact under the elevated than ambient CO 2 level. Mycorrhizae decreased relative interaction index (RII) of C 3 plants under both ambient and elevated CO 2 , but mycorrhizae increased RII of C 4 plants only under elevated CO 2 . Elevated CO 2 and mycorrhizal inoculation enhanced 15 N and total N and P uptake of C 4 barnyard grass in mixture but had no effects on N and P acquisition of C 3 upland rice, thus altering the distribution of N and P between the species in mixture. These results implied that CO 2 stimulation of mycorrhizae and their nutrient acquisition may impact competitive interaction of C 4 barnyard grass and C 3 upland rice under future CO 2 scenarios.}, number={2}, journal={ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY}, author={Tang, Jianjun and Xu, Liming and Chen, Xin and Hu, Shuijin}, year={2009}, pages={227–235} }
 @article{liu_gumpertz_hu_ristaino_2008, title={Effect of prior tillage and soil fertility amendments on dispersal of Phytophthora capsici and infection of pepper}, volume={120}, ISSN={["1573-8469"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-38649084121&partnerID=MN8TOARS}, DOI={10.1007/s10658-007-9216-7}, number={3}, journal={EUROPEAN JOURNAL OF PLANT PATHOLOGY}, author={Liu, Bo and Gumpertz, Marcia L. and Hu, Shuijin and Ristaino, Jean Beagle}, year={2008}, month={Mar}, pages={273–287} }
 @article{shao_wang_dean_lin_gao_hu_2008, title={Expression of a harpin-encoding gene in rice confers durable nonspecific resistance to Magnaporthe grisea}, volume={6}, ISSN={["1467-7644"]}, DOI={10.1111/j.1467-7652.2007.00304.x}, abstractNote={Engineering durable nonspecific resistance to phytopathogens is one of the ultimate goals of plant breeding. However, most attempts to reach this goal fail as a result of rapid changes in pathogen populations and the sheer diversity of pathogen infection mechanisms. In this study, we show that the expression of a harpin-encoding gene (hrf1), derived from Xanthomonas oryzae pv. oryzae, confers nonspecific resistance in rice to the blast fungus Magnaporthe grisea. Transgenic plants and their T1-T7 progenies were highly resistant to all major M. grisea races in rice-growing areas along the Yangtze River, China. The expression of defence-related genes was activated in resistant transgenic plants, and the formation of melanized appressoria, which is essential for foliar infection, was inhibited on plant leaves. These results suggest that harpins may offer new opportunities for generating broad-spectrum disease resistance in other crops.}, number={1}, journal={PLANT BIOTECHNOLOGY JOURNAL}, author={Shao, Min and Wang, Jinsheng and Dean, Ralph A. and Lin, Yongjun and Gao, Xuewen and Hu, Shuijin}, year={2008}, month={Jan}, pages={73–81} }
 @article{wang_liu_wang_gong_hua_pang_hu_yang_2008, title={Impacts of methamidophos on the biochemical, catabolic, and genetic characteristics of soil microbial communities}, volume={40}, ISSN={["0038-0717"]}, DOI={10.1016/j.soilbio.2007.10.012}, abstractNote={Methamidophos is an organophosphate pesticide with high toxicity and may significantly affect soil microbes. However, the magnitude of this effect is unclear. We examined the effect of low and high inputs of methamidophos on the structure of the soil microbial community, and the catabolic activity and the genetic diversity of the bacterial community using the polyphasic approaches of microbial biomass, phospholipid fatty acids (PLFAs), community-level catabolic profiles (CLCPs), and amplified ribosomal DNA restriction analysis (ARDRA) patterns. Our results indicated that high methamidophos inputs significantly reduced total microbial biomass carbon (Cmic) and fungal biomass, but increased Gram-negative bacteria with no significant effects on the Gram-positive bacteria. Interestingly, CLCPs patterns showed that high methamidophos inputs also significantly improved the catabolic activity of Gram-negative bacteria. The ARDRA pattern showed that the genetic diversity of the bacterial community decreased under chemical stress. Furthermore, changes in the microbial parameters examined were less significant under low inputs than high inputs of methamidophos, suggesting a dosage effect of methamidophos on the microbial community. Our results provide the first evidence that methamidophos differentially affected components of the soil microbial community through inhibiting fungal growth but enhancing the biomass and catabolic activity of Gram-negative bacteria.}, number={3}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Wang, Meng-Cheng and Liu, Ye-Hao and Wang, Qiong and Gong, Ming and Hua, Xiao-Mei and Pang, Yan-Jun and Hu, Shuijin and Yang, Yong-Hua}, year={2008}, month={Mar}, pages={778–788} }
 @article{liu_tu_hu_gumpertz_ristaino_2007, title={Effect of organnic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors and the incidence of Southern blight}, volume={37}, ISSN={["1873-0272"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34748831003&partnerID=MN8TOARS}, DOI={10.1016/j.apsoil.2007.06.007}, abstractNote={The objectives of our research were to evaluate the impact of organic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors including soil microbial species and functional diversity and their effect on the Basidiomycete plant pathogen Sclerotium rolfsii, causal agent of Southern blight. Soils from 10 field locations including conventional, organic and sustainable farms were sampled and assayed for disease suppressiveness in greenhouse assays, and soil quality indicators. Soils from organic and sustainable farms were more suppressive to Southern blight than soils from conventional farms. Soils from organic farms had improved soil chemical factors and higher levels of extractable C and N, higher microbial biomass carbon and nitrogen, and net mineralizable N. In addition, soil microbial respiration was higher in soils from organic than sustainable or conventional farms, indicating that microbial activity was greater in these soils. Populations of fungi and thermophiles were significantly higher in soils from organic and sustainable than conventional fields. The diversity of bacterial functional communities was also greater in soils from organic farms, while species diversity was similar. Soils from organic and sustainable farms had improved soil health as indicated by a number of soil physical, chemical and biological factors and reduced disease.}, number={3}, journal={APPLIED SOIL ECOLOGY}, author={Liu, Bo and Tu, Cong and Hu, Shuijin and Gumpertz, Marcia and Ristaino, Jean Beagle}, year={2007}, month={Nov}, pages={202–214} }
 @article{yang_tang_chen_hu_2007, title={Effects of coexisting plant species on soil microbes and soil enzymes in metal lead contaminated soils}, volume={37}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2007.07.004}, abstractNote={It is not clear whether plant species coexistence can offset the impacts of heavy metal lead (Pb) on soil microbes and soil enzyme activities. We conducted a factorial experiment to investigate the effects of three plant species combinations (1, 2 and 4 species) on soil microbial and soil enzyme properties under three Pb concentrations (0, 300 and 600 mg kg−1 soil). Microbial biomass carbon (MBC), BIOLOG profiles of soil microbes and soil enzyme activities were measured. Under monoculture, elevated Pb did not reduce soil MBC, had no effects on activities of urease, acid phosphatase and dehydrogenase, but stimulated the activity of alkaline phosphatase. Compared to monoculture, plant species coexistence did not significantly affect soil microbial biomass C but increased microbial functional group diversity index and urease activity under different Pb concentrations. In addition, microbial community structure diverged among plant coexistence treatments under each Pb concentration. These results suggested that coexistence of plant species might alleviate the effects of metal lead on soil microbes and reducing metal lead effect on urease activity.}, number={3}, journal={APPLIED SOIL ECOLOGY}, author={Yang, Ruyi and Tang, Jianjun and Chen, Xin and Hu, Shuijin}, year={2007}, month={Nov}, pages={240–246} }
 @article{liu_gumpertz_hu_ristaino_2007, title={Long-term effects of organic and synthetic soil fertility amendments on soil microbial communities and the development of southern blight}, volume={39}, ISSN={["1879-3428"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250215285&partnerID=MN8TOARS}, DOI={10.1016/j.soilbio.2007.04.001}, abstractNote={The effects of tillage and soil fertility amendments on the relationship between the suppressiveness of soils to southern blight and soil physical, chemical and biological factors were examined in experimental station plots in North Carolina. Main plots were either tilled frequently or surface-mulched after one initial tillage. Organic soil amendments including composted cotton gin trash, composted poultry manure, an incorporated rye–vetch green manure, or synthetic fertilizer were applied to subplots in a split-plot design experiment. Incidence of southern blight was lower in surfaced-mulched than tilled soils. Incidence of southern blight was also lower in soils amended with cotton gin trash than those amended with poultry manure, rye–vetch green manure or synthetic fertilizer. Soil water content was negatively correlated with the incidence of disease in both years. Disease incidence was negatively correlated with the level of potassium, calcium, cation exchange capacity (CEC), base saturation (BS) and humic matter in 2002, and net mineralizable nitrogen in 2001. Although, populations of thermophilic organisms were significantly higher in soils amended with cotton gin trash than the other three fertility amendments in each year, there was no significant correlation between the populations of thermophiles and incidence of the disease. Bacterial community diversity indices based on community-level physiological profiling (CLPP) and denaturing gradient gel electrophoresis (DGGE) were significantly higher in soils amended with cotton gin trash than those amended with poultry manure, green manure or synthetic fertilizer. There was a significant negative correlation between the incidence of southern blight, and CLPP and DGGE diversity indices. Greater differences in the richness of bacterial functional groups than genotypes were observed. These results demonstrate that organic soil fertility amendments and cotton gin trash in particular, reduced the development of the disease and affected soil physical, chemical and biological parameters.}, number={9}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Liu, Bo and Gumpertz, Marcia L. and Hu, Shuijin and Ristaino, Jean Beagle}, year={2007}, month={Sep}, pages={2302–2316} }
 @article{chen_tu_burton_watson_burkey_hu_2007, title={Plant nitrogen acquisition and interactions under elevated carbon dioxide: impact of endophytes and mycorrhizae}, volume={13}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2007.01347.x}, abstractNote={Both endophytic and mycorrhizal fungi interact with plants to form symbiosis in which the fungal partners rely on, and sometimes compete for, carbon (C) sources from their hosts. Changes in photosynthesis in host plants caused by atmospheric carbon dioxide (CO2) enrichment may, therefore, influence those mutualistic interactions, potentially modifying plant nutrient acquisition and interactions with other coexisting plant species. However, few studies have so far examined the interactive controls of endophytes and mycorrhizae over plant responses to atmospheric CO2 enrichment. Using Festuca arundinacea Schreb and Plantago lanceolata L. as model plants, we examined the effects of elevated CO2 on mycorrhizae and endophyte (Neotyphodium coenophialum) and plant nitrogen (N) acquisition in two microcosm experiments, and determined whether and how mycorrhizae and endophytes mediate interactions between their host plant species. Endophyte-free and endophyte-infected F. arundinacea varieties, P. lanceolata L., and their combination with or without mycorrhizal inocula were grown under ambient (400 μmol mol−1) and elevated CO2 (ambient + 330 μmol mol−1). A 15N isotope tracer was used to quantify the mycorrhiza-mediated plant acquisition of N from soil. Elevated CO2 stimulated the growth of P. lanceolata greater than F. arundinacea, increasing the shoot biomass ratio of P. lanceolata to F. arundinacea in all the mixtures. Elevated CO2 also increased mycorrhizal root colonization of P. lanceolata, but had no impact on that of F. arundinacea. Mycorrhizae increased the shoot biomass ratio of P. lanceolata to F. arundinacea under elevated CO2. In the absence of endophytes, both elevated CO2 and mycorrhizae enhanced 15N and total N uptake of P. lanceolata but had either no or even negative effects on N acquisition of F. arundinacea, altering N distribution between these two species in the mixture. The presence of endophytes in F. arundinacea, however, reduced the CO2 effect on N acquisition in P. lanceolata, although it did not affect growth responses of their host plants to elevated CO2. These results suggest that mycorrhizal fungi and endophytes might interactively affect the responses of their host plants and their coexisting species to elevated CO2.}, number={6}, journal={GLOBAL CHANGE BIOLOGY}, author={Chen, Xin and Tu, Cong and Burton, Michael G. and Watson, Dorothy M. and Burkey, Kent O. and Hu, Shuijin}, year={2007}, month={Jun}, pages={1238–1249} }
 @article{tu_booker_watson_chen_rufty_shi_hu_2006, title={Mycorrhizal mediation of plant N acquisition and residue decomposition: Impact of mineral N inputs}, volume={12}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2006.01149.x}, abstractNote={Mycorrhizas are ubiquitous plant–fungus mutualists in terrestrial ecosystems and play important roles in plant resource capture and nutrient cycling. Sporadic evidence suggests that anthropogenic nitrogen (N) input may impact the development and the functioning of arbuscular mycorrhizal (AM) fungi, potentially altering host plant growth and soil carbon (C) dynamics. In this study, we examined how mineral N inputs affected mycorrhizal mediation of plant N acquisition and residue decomposition in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that either prevented or allowed AM fungal hyphae but not plant roots to grow into the TEST compartments. Wild oat (Avena fatua L.) was planted in the HOST compartments that had been inoculated with either a single species of AM fungus, Glomus etunicatum, or a mixture of AM fungi including G. etunicatum. Mycorrhizal contributions to plant N acquisition and residue decomposition were directly assessed by introducing a mineral 15N tracer and 13C-rich residues of a C4 plant to the TEST compartments. Results from 15N tracer measurements showed that AM fungal hyphae directly transported N from the TEST soil to the host plant. Compared with the control with no penetration of AM fungal hyphae, AM hyphal penetration led to a 125% increase in biomass 15N of host plants and a 20% reduction in extractable inorganic N in the TEST soil. Mineral N inputs to the HOST compartments (equivalent to 5.0 g N m−2 yr−1) increased oat biomass and total root length colonized by mycorrhizal fungi by 189% and 285%, respectively, as compared with the no-N control. Mineral N inputs to the HOST plants also reduced extractable inorganic N and particulate residue C proportion by 58% and 12%, respectively, in the corresponding TEST soils as compared to the no-N control, by stimulating AM fungal growth and activities. The species mixture of mycorrhizal fungi was more effective in facilitating N transport and residue decomposition than the single AM species. These findings indicate that low-level mineral N inputs may significantly enhance nutrient cycling and plant resource capture in terrestrial ecosystems via stimulation of root growth, mycorrhizal functioning, and residue decomposition. The long-term effects of these observed alterations on soil C dynamics remain to be investigated.}, number={5}, journal={GLOBAL CHANGE BIOLOGY}, author={Tu, C and Booker, FL and Watson, DM and Chen, X and Rufty, TW and Shi, W and Hu, SJ}, year={2006}, month={May}, pages={793–803} }
 @article{hu_tu_chen_gruver_2006, title={Progressive N limitation of plant response to elevated CO2: a microbiological perspective}, volume={289}, ISSN={["0032-079X"]}, DOI={10.1007/s11104-006-9093-4}, number={1-2}, journal={PLANT AND SOIL}, author={Hu, Shuijin and Tu, Cong and Chen, Xin and Gruver, Joel B.}, year={2006}, month={Nov}, pages={47–58} }
 @article{tu_louws_creamer_mueller_brownie_fager_bell_hu_2006, title={Responses of soil microbial biomass and N availability to transition strategies from conventional to organic farming systems}, volume={113}, ISSN={["1873-2305"]}, DOI={10.1016/j.agee.2005.09.013}, abstractNote={Abstract Organic farming can enhance soil biodiversity, alleviate environmental concerns and improve food safety through eliminating the applications of synthetic chemicals. However, yield reduction due to nutrient limitation and pest incidence in the early stages of transition from conventional to organic systems is a major concern for organic farmers, and is thus a barrier to implementing the practice of organic farming. Therefore, identifying transition strategies that minimize yield loss is critical for facilitating the implementation of organic practices. Soil microorganisms play a dominant role in nutrient cycling and pest control in organic farming systems, and their responses to changes in soil management practices may critically impact crop growth and yield. Here we examined soil microbial biomass and N supply in response to several strategies for transitioning from conventional to organic farming systems in a long-term field experiment in Goldsboro, NC, USA. The transitional strategies included one fully organic strategy (ORG) and four reduced-input strategies (withdrawal of each or gradual reduction of major conventional inputs—synthetic fertilizers, pesticides (insecticides/fungicides), and herbicides), with a conventional practice (CNV) serving as a control. Microbial biomass and respiration rate were more sensitive to changes in soil management practices than total C and N. In the first 2 years, the ORG was most effective in enhancing soil microbial biomass C and N among the transition strategies, but was accompanied with high yield losses. By the third year, soil microbial biomass C and N in the reduced-input transition strategies were statistically significantly greater than those in the CNV (averaging 32 and 35% higher, respectively), although they were slightly lower than those in the ORG (averaging 13 and 17% lower, respectively). Soil microbial respiration rate and net N mineralization in all transitional systems were statistically significantly higher than those in the CNV (averagely 83 and 66% greater, respectively), with no differences among the various transition strategies. These findings suggest that the transitional strategies that partially or gradually reduce conventional inputs can serve as alternatives that could potentially minimize economic hardships as well as benefit microbial growth during the early stages of transition to organic farming systems.}, number={1-4}, journal={AGRICULTURE ECOSYSTEMS & ENVIRONMENT}, author={Tu, C and Louws, FJ and Creamer, NG and Mueller, JP and Brownie, C and Fager, K and Bell, M and Hu, SJ}, year={2006}, month={Apr}, pages={206–215} }
 @article{tu_ristaino_hu_2006, title={Soil microbial biomass and activity in organic tomato farming systems: Effects of organic inputs and straw mulching}, volume={38}, ISSN={["1879-3428"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-29744443972&partnerID=MN8TOARS}, DOI={10.1016/j.soilbio.2005.05.002}, abstractNote={Organic farming is rapidly expanding worldwide. Plant growth in organic systems greatly depends on the functions performed by soil microbes, particularly in nutrient supply. However, the linkages between soil microbes and nutrient availability in organically managed soils are not well understood. We conducted a long-term field experiment to examine microbial biomass and activity, and nutrient availability under four management regimes with different organic inputs. The experiment was initiated in 1997 by employing different practices of organic farming in a coastal sandy soil in Clinton, NC, USA. Organic practices were designed by applying organic substrates with different C and N availability, either in the presence or absence of wheat–straw mulch. The organic substrates used included composted cotton gin trash (CGT), animal manure (AM) and rye/vetch green manure (RV). A commercial synthetic fertilizer (SF) was used as a conventional control. Results obtained in both 2001 and 2002 showed that microbial biomass and microbial activity were generally higher in organically than conventionally managed soils with CGT being most effective. The CGT additions increased soil microbial biomass C and activity by 103–151% and 88–170% over a period of two years, respectively, leading to a 182–285% increase in potentially mineralizable N, compared to the SF control. Straw mulching further enhanced microbial biomass, activity, and potential N availability by 42, 64, and 30%, respectively, relative to non-mulched soils, likely via improving C and water availability for soil microbes. The findings that microbial properties and N availability for plants differed under different organic input regimes suggest the need for effective residue managements in organic tomato farming systems.}, number={2}, journal={SOIL BIOLOGY & BIOCHEMISTRY}, author={Tu, C and Ristaino, JB and Hu, SJ}, year={2006}, month={Feb}, pages={247–255} }
 @article{chen_wu_tang_hu_2005, title={Arbuscular mycorrhizae enhance metal lead uptake and growth of host plants under a sand culture experiment}, volume={60}, ISSN={["1879-1298"]}, DOI={10.1016/j.chemosphere.2005.01.029}, abstractNote={A sand culture experiment was conducted to investigate whether mycorrhizal colonization and mycorrhizal fungal vesicular numbers were influenced by metal lead, and whether mycorrhizae enhance host plants tolerance to metal lead. Metal lead was applied as Pb(NO3)2 in solution at three levels (0, 300 and 600 mg kg−1 sand). Five mycorrhizal host plant species, Kummerowia striata (Thunb.) Schindl, Ixeris denticulate L., Lolium perenne L., Trifolium repens L. and Echinochloa crusgalli var. mitis were used to examine Pb-mycorrhizal interactions. The arbuscular mycorrhizal inoculum consisted of mixed spores of mycorrhizal fungal species directly isolated from orchard soil. Compared to the untreated control, both Pb concentrations reduced mycorrhizal colonization by 3.8–70.4%. Numbers of AM fungal vesicles increased by 13.2–51.5% in 300 mg Pb kg−1 sand but decreased by 9.4–50.9% in 600 mg Pb kg−1 sand. Mycorrhizae significantly enhanced Pb accumulation both in shoot by 10.2–85.5% and in root by 9.3–118.4%. Mycorrhizae also enhanced shoot biomass and shoot P concentration under both Pb concentrations. Root/shoot ratios of Pb concentration were higher in highly mycorrhizal plant species (K.striata, I. denticulate, and E. crusgalli var. mitis) than that in poorly mycorrhizal ones (L. perenne and T. repens,). Mycorrhizal inoculation increased the root/shoot ratio of Pb concentration of highly mycorrhizal plant species by 7.6–57.2% but did not affect the poorly mycorrhizal ones. In the treatments with 300 Pb mg kg−1 sand, plant species with higher vesicular numbers tended to show higher root/shoot ratios of the Pb concentration. We suggest that under an elevated Pb condition, mycorrhizae could promote plant growth by increasing P uptake and mitigate Pb toxicity by sequestrating more Pb in roots.}, number={5}, journal={CHEMOSPHERE}, author={Chen, X and Wu, CH and Tang, JJ and Hu, SJ}, year={2005}, month={Jul}, pages={665–671} }
 @article{chen_tang_zhi_hu_2005, title={Arbuscular mycorrhizal colonization and phosphorus acquisition of plants: effects of coexisting plant species}, volume={28}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2004.07.009}, abstractNote={Arbuscular mycorrhizal (AM) fungi influence interactions among plant species through enhancing nutrient uptake and possibly facilitating nutrient transport among plants. However, the effects of one plant species on coexisting plant species with regard to mycorrhizal colonization are not well understood. We examined root mycorrhizal colonization and phosphorus (P) acquisition of plants in a highly P-limiting soil in Lanxi city, Zhejiang, China from the year 2000 to 2002. Three dominant native plant species with different mycorrhizal properties, Digitaria ciliaris (poorly mycorrhizal species), Ixeris denticulate (moderately mycorrhizal species) and Kummerowia striata (highly mycorrhizal species), were planted in experimental plots. In the monocultures, K. striata was found to have the highest infection and D. ciliaris the lowest mycorrhizal infection, but shoot P-concentration was higher in both I. denticulate and D. ciliaris than that in K. striata. In the mixtures, D. ciliaris and I. denticulate did not significantly affect the mycorrhizal colonization, spore production and shoot P-concentration of K. striata plants, but K. striata and I. denticulate significantly increased root mycorrhizal colonization and shoot P-concentration of D. ciliaris. K. striata enhanced but D. ciliaris reduced mycorrhizal infection and shoot P-concentration of I. denticulate. These results suggested that highly mycorrhizal plant species may positively impact coexisting species with respect to mycorrhizal colonization and P acquisition, but the effects on poorly mycorrhizal species are less predictable.}, number={3}, journal={APPLIED SOIL ECOLOGY}, author={Chen, X and Tang, JJ and Zhi, GY and Hu, SJ}, year={2005}, month={Mar}, pages={259–269} }
 @article{booker_prior_torbert_fiscus_pursley_hu_2005, title={Decomposition of soybean grown under elevated concentrations of CO2 and O-3}, volume={11}, DOI={10.1111/j.1365.2486.2005.00939.x}, number={4}, journal={Global Change Biology}, author={Booker, F. L. and Prior, S. A. and Torbert, H. A. and Fiscus, E. L. and Pursley, W. A. and Hu, Shuijin}, year={2005}, pages={685–698} }
 @article{hu_wu_burkey_firestone_2005, title={Plant and microbial N acquisition under elevated atmospheric CO2 in two mesocosm experiments with annual grasses}, volume={11}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2005.00905.x}, abstractNote={The impact of elevated CO2 on terrestrial ecosystem C balance, both in sign or magnitude, is not clear because the resulting alterations in C input, plant nutrient demand and water use efficiency often have contrasting impacts on microbial decomposition processes. One major source of uncertainty stems from the impact of elevated CO2 on N availability to plants and microbes. We examined the effects of atmospheric CO2 enrichment (ambient+370 μmol mol−1) on plant and microbial N acquisition in two different mesocosm experiments, using model plant species of annual grasses of Avena barbata and A. fatua, respectively. The A. barbata experiment was conducted in a N-poor sandy loam and the A. fatua experiment was on a N-rich clayey loam. Plant–microbial N partitioning was examined through determining the distribution of a 15N tracer. In the A. barbata experiment, 15N tracer was introduced to a field labeling experiment in the previous year so that 15N predominantly existed in nonextractable soil pools. In the A. fatua experiment, 15N was introduced in a mineral solution [(15NH4)2SO4 solution] during the growing season of A. fatua. Results of both N budget and 15N tracer analyses indicated that elevated CO2 increased plant N acquisition from the soil. In the A. barbata experiment, elevated CO2 increased plant biomass N by ca. 10% but there was no corresponding decrease in soil extractable N, suggesting that plants might have obtained N from the nonextractable organic N pool because of enhanced microbial activity. In the A. fatua experiment, however, the CO2-led increase in plant biomass N was statistically equal to the reduction in soil extractable N. Although atmospheric CO2 enrichment enhanced microbial biomass C under A. barbata or microbial activity (respiration) under A. fatua, it had no significant effect on microbial biomass N in either experiment. Elevated CO2 increased the colonization of A. fatua roots by arbuscular mycorrhizal fungi, which coincided with the enhancement of plant competitiveness for soluble soil N. Together, these results suggest that elevated CO2 may tighten N cycling through facilitating plant N acquisition. However, it is unknown to what degree results from these short-term microcosm experiments can be extrapolated to field conditions. Long-term studies in less-disturbed soils are needed to determine whether CO2-enhancement of plant N acquisition can significantly relieve N limitation over plant growth in an elevated CO2 environment.}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Hu, SJ and Wu, JS and Burkey, KO and Firestone, MK}, year={2005}, month={Feb}, pages={213–223} }
 @article{zhang_rui_tu_diab_louws_mueller_creamer_bell_wagger_hu_2005, title={Responses of soil microbial community structure and diversity to agricultural deintensification}, volume={15}, number={4}, journal={Pedosphere}, author={Zhang, W. J. and Rui, W. Y. and Tu, C. and Diab, H. G. and Louws, F. J. and Mueller, J. P. and Creamer, N. and Bell, M. and Wagger, M. G. and Hu, S.}, year={2005}, pages={440–447} }
 @article{zhang_parker_luo_wan_wallace_hu_2005, title={Soil microbial responses to experimental warming and clipping in a tallgrass prairie}, volume={11}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2005.00902.x}, abstractNote={Global surface temperature is predicted to increase by 1.4–5.8°C by the end of this century. However, the impacts of this projected warming on soil C balance and the C budget of terrestrial ecosystems are not clear. One major source of uncertainty stems from warming effects on soil microbes, which exert a dominant influence on the net C balance of terrestrial ecosystems by controlling organic matter decomposition and plant nutrient availability. We, therefore, conducted an experiment in a tallgrass prairie ecosystem at the Great Plain Apiaries (near Norman, OK) to study soil microbial responses to temperature elevation of about 2°C through artificial heating in clipped and unclipped field plots. While warming did not induce significant changes in net N mineralization, soil microbial biomass and respiration rate, it tended to reduce extractable inorganic N during the second and third warming years, likely through increasing plant uptake. In addition, microbial substrate utilization patterns and the profiles of microbial phospholipid fatty acids (PLFAs) showed that warming caused a shift in the soil microbial community structure in unclipped subplots, leading to the relative dominance of fungi as evidenced by the increased ratio of fungal to bacterial PLFAs. However, no warming effect on soil microbial community structure was found in clipped subplots where a similar scale of temperature increase occurred. Clipping also significantly reduced soil microbial biomass and respiration rate in both warmed and unwarmed plots. These results indicated that warming-led enhancement of plant growth rather than the temperature increase itself may primarily regulate soil microbial response. Our observations show that warming may increase the relative contribution of fungi to the soil microbial community, suggesting that shifts in the microbial community structure may constitute a major mechanism underlying warming acclimatization of soil respiration.}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Zhang, W and Parker, KM and Luo, Y and Wan, S and Wallace, LL and Hu, S}, year={2005}, month={Feb}, pages={266–277} }
 @article{zhang_zhu_hu_2005, title={Soil resource availability impacts microbial response to organic carbon and inorganic nitrogen inputs}, volume={17}, number={5}, journal={Journal of Environmental Sciences (China)}, author={Zhang, W. J. and Zhu, W. and Hu, S.}, year={2005}, pages={705–710} }
 @article{hu_weijian_2004, title={Impact of global change on biological processes in soil: Implications for agroecosystem management}, volume={12}, ISBN={1542-7528}, DOI={10.1300/j411v12n01_02}, abstractNote={SUMMARY The Earth is undergoing rapid environmental changes due to human activities. Three components of the ongoing global change, elevated atmospheric CO2, N deposition, and global warming, may significantly impact soil biota directly through modifying the physical and chemical environment, and indirectly through altering aboveground plant growth and community composition. The biomass, community structure, and activities of microbes and animals in soil as well as their interactions will likely be affected, leading to changes in ecological processes and functions. Biological processes that may be modified by global change include organic matter decomposition, N mineralization, food web interaction, and biotic N fixation. Lack of the complexity in agroecosystems may amplify the effects of global change on many biological processes in agricultural soils. However, minimizing human disturbance and thus increasing the complexity of agroecosystems may enhance the potential of C sequestration in agricultural so...}, number={1}, journal={Journal of Crop Improvement}, author={Hu, Shuijin and WeiJian, Zhang}, year={2004}, pages={289} }
 @article{tu_koenning_hu_2003, title={Root-parasitic nematodes enhance soil microbial activities and nitrogen mineralization}, volume={46}, ISSN={["1432-184X"]}, DOI={10.1007/s00248-002-1068-2}, number={1}, journal={MICROBIAL ECOLOGY}, author={Tu, C and Koenning, SR and Hu, S}, year={2003}, month={Jul}, pages={134–144} }
 @article{diab_hu_benson_2003, title={Suppression of Rhizoctonia solani on impatiens by enhanced microbial activity in composted swine waste-amended potting mixes}, volume={93}, ISSN={["0031-949X"]}, DOI={10.1094/PHYTO.2003.93.9.1115}, abstractNote={Peat moss-based potting mix was amended with either of two composted swine wastes, CSW1 and CSW2, at rates from 4 to 20% (vol/vol) to evaluate suppression of pre-emergence damping-off of impatiens (Impatiens balsamina) caused by Rhizoctonia solani (anastomosis group-4). A cucumber bioassay was used prior to each impatiens experiment to monitor maturity of compost as the compost aged in a curing pile by evaluating disease suppression toward both Pythium ultimum and R. solani. At 16, 24, 32, and 37 weeks after composting, plug trays filled with compost-amended potting mix were seeded with impatiens and infested with R. solani to determine suppression of damping-off. Pre-emergence damping-off was lower for impatiens grown in potting mix amended with 20% CSW1 than in CSW2-amended and nonamended mixes. To identify relationships between disease suppression and microbial parameters, samples of mixes were collected to determine microbial activity, biomass carbon and nitrogen, functional diversity, and population density. Higher rates of microbial activity were observed with increasing rates of CSW1 amendment than with CSW2 amendments. Microbial biomass carbon and nitrogen also were higher in CSW1-amended mixes than in CSW2-amended potting mixes 1 day prior to seeding and 5 weeks after seeding. Principal component analysis of Biolog-GN2 profiles showed different functional diversities between CSW1- and CSW2-amended mixes. Furthermore, mixes amended with CSW1 had higher colony forming units of fungi, endospore-forming bacteria, and oligotrophic bacteria. Our results suggest that enhanced microbial activity, functional and population diversity of stable compost-amended mix were associated with suppressiveness to Rhizoctonia damping-off in impatiens.}, number={9}, journal={PHYTOPATHOLOGY}, author={Diab, HG and Hu, S and Benson, DM}, year={2003}, month={Sep}, pages={1115–1123} }
 @article{mueller_barbercheck_bell_brownie_creamer_hitt_hu_king_linker_louws_et al._2002, title={Development and implementation of a long-term agricultural systems study: Challenges and opportunities}, volume={12}, number={3}, journal={HortTechnology}, author={Mueller, J. P. and Barbercheck, M. E. and Bell, M. and Brownie, C. and Creamer, N. G. and Hitt, A. and Hu, S. and King, L. and Linker, H. M. and Louws, F. J. and et al.}, year={2002}, pages={362–368} }
 @article{hu_chapin_firestone_field_chiariello_2001, title={Nitrogen limitation of microbial decomposition in a grassland under elevated CO2}, volume={409}, ISSN={["0028-0836"]}, DOI={10.1038/35051576}, number={6817}, journal={NATURE}, author={Hu, S and Chapin, FS and Firestone, MK and Field, CB and Chiariello, NR}, year={2001}, month={Jan}, pages={188–191} }