@article{franzluebbers_broome_pritchett_wagger_lowder_woodruff_lovejoy_2021, title={Multispecies cover cropping promotes soil health in no-tillage cropping systems of North Carolina}, volume={76}, ISSN={["1941-3300"]}, DOI={10.2489/jswc.2021.00087}, abstractNote={Moving agricultural production systems toward a greater level of soil health is needed for sustainability. Conservation agricultural systems utilizing no or minimum tillage are an important step forward, but enhancing carbon (C) inputs with diverse cover crops and facilitating biologically active nitrogen (N) cycling are also needed. Summer cash-crop systems, particularly in the warm-humid region of the southeastern United States, may benefit from multispecies winter cover cropping if sufficient biomass were produced. We implemented a research and demonstration project utilizing multispecies cover cropping in 15 counties of North Carolina during 2015 to 2019 to assess biomass production and its effect on surface-soil properties. Winter cover crop biomass production was variable among locations, but exceeded 3,790 kg ha–1 in one-third of trials. Nitrogen contained in aboveground cover crop biomass exceeded 60 kg ha–1 in the upper third of trials. Of 30 soil properties measured in each site-year (n = 31) at depths of 0 to 5 and 5 to 15 cm, soil-test biological activity, C mineralization during 24 days, total soil N, and Mehlich-III phosphorus (P) and potassium (K) were most consistently affected when comparing multispecies cover cropping with either no or single-species cover cropping. Despite relatively short duration of evaluations (i.e., mostly one to two years), we were able to elucidate that winter multispecies cover cropping has potential to improve soil health conditions in the region. Soil-test biological activity demonstrated the living nature of soil and was sensitive to conservation agricultural management. The support of a hands-on farmer and adviser network encouraged success.}, number={3}, journal={JOURNAL OF SOIL AND WATER CONSERVATION}, author={Franzluebbers, A. J. and Broome, S. W. and Pritchett, K. L. and Wagger, M. G. and Lowder, N. and Woodruff, S. and Lovejoy, M.}, year={2021}, pages={263–275} }
 @article{roper_osmond_heitman_wagger_reberg-horton_2017, title={Soil Health Indicators Do Not Differentiate among Agronomic Management Systems in North Carolina Soils}, volume={81}, ISSN={["1435-0661"]}, DOI={10.2136/sssaj2016.12.0400}, abstractNote={Recent soil tests evaluating “soil health” on a broad scale may not properly consider the intrinsic limitations of soil properties, and have not been assessed in regionally unique soil conditions. To evaluate three soil tests in North Carolina, we used long-term agronomic management trials from three distinct physiographic regions: mountain (22 yr), piedmont (32 yr), and coastal plain (17 yr). Mountain and coastal plain trials included combinations of organic or chemical management with or without tillage; the piedmont trial included nine different tillage treatments. Soil samples were collected and submitted for analysis as recommended by the North Carolina Department of Agriculture and Consumer Services, Haney soil health test (HSHT), and Cornell comprehensive assessment of soil health (CASH). Plant nutrient concentrations varied but were still sufficient for crops. The CASH physical soil indicators, such as surface hardness and aggregate stability, were not statistically different, regardless of tillage intensity or management. Biological soil indicators (e.g., CO₂ respiration) responded differently to management, but this differentiation was inconsistent among locations and tests. Despite many years of conservation management, the CASH results described mountain soils as “low” or “very low” soil health for all but no-till organic management, which received a “medium” score. The HSHT results considered soil from all but moldboard plowing (piedmont) to be in good health. Finally, there was no correlation between soil health tests and crop yields from North Carolina soils. Soil health tests should be calibrated to better differentiate among soil management effects that vary depending on intrinsic soil limitations.}, number={4}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Roper, Wayne R. and Osmond, Deanna L. and Heitman, Joshua L. and Wagger, Michael G. and Reberg-Horton, S. Chris}, year={2017}, pages={828–843} }
 @article{komatsuzaki_wagger_2015, title={Nitrogen recovery by cover crops in relation to time of planting and growth termination}, volume={70}, ISSN={["1941-3300"]}, DOI={10.2489/jswc.70.6.385}, abstractNote={Residual fertilizer nitrogen (N) in soil represents a potential environmental contaminant because of the risk of nitrate (NO3) leaching into ground water. Winter annual grass cover crops can conserve residual soil N; however, their ability to recover N greatly varies with management. A two-year field experiment in the North Carolina Coastal Plain on a State fine sandy loam (fine-loamy, mixed, thermic Typic Hapludult) compared dry matter (DM), N accumulation, and soil inorganic N following rye (Secale cereale L.), winter wheat (Triticum aestivum L.), triticale (Triticum secale L.), black oats (Avena strigosa L.), and fallow (native weeds) in relation to planting (October, November, and December) and growth termination (early March, early April, and late April/early May) dates and levels of residual soil N. Cover crop DM and N accumulations decreased with successive planting date delays (November and December) for each growth termination date in the following spring. In 2000, cumulative DM yields of October- and November-planted cover crops were 3.17 Mg ha−1 (1.41 tn ac−1) and 3.74 Mg ha−1 (1.66 tn ac−1), respectively, which were significantly greater than those of December-planted cover crops (1.90 Mg ha−1 [0.84 tn ac−1]) at the second growth termination date (early April). Cover crop N accumulation increased with a delay in growth termination, although the interaction between cover crop species and the planting date varied. October planting of rye and triticale showed greater N accumulation at a March growth termination date, averaging 37.8 kg N ha−1 (33.7 lb N ac−1) for rye and 37.6 kg N ha−1 (33.5 lb N ac−1) for triticale; these values were 7.8% and 14.1% higher than those of black oat and wheat, respectively, at the same planting and growth termination dates. November-planted wheat showed in the highest N accumulation (average, 57.9 kg N ha−1 [51.7 lb N ac−1]) at the late April/early May termination date; this was 3.8% to 7.9% higher than that of other species. In contrast, black oat showed a greater ability to scavenge soil residual N with a late planting and growth termination date combination (average, 58.7 kg N ha−1 [52.4 lb N ac−1]). The cover crop planting date affected soil inorganic N distribution at each termination date, with an October planting date resulting in lower soil profile inorganic N levels than November and December planting dates. Lower soil inorganic N concentrations were strongly associated with increases in cover crop DM and N accumulation for each growth termination date. These results should help growers identify the best niche for a cover crop with respect to recovering residual soil N in their various rotations.}, number={6}, journal={JOURNAL OF SOIL AND WATER CONSERVATION}, author={Komatsuzaki, M. and Wagger, M. G.}, year={2015}, pages={385–398} }
 @article{mcginnis_wagger_warren_bilderback_2010, title={Nutrient contribution and release kinetics of vermicompost amended pine bark}, volume={18}, DOI={10.1080/1065657x.2010.10736941}, abstractNote={The composting of organic waste materials using earthworms yields the value-added product vermicompost (VC). The use of VC as a growing substrate amendment for containerized horticultural crop production is a sustainable nutrient management approach which can benefit crop production by providing plant nutrients and improving crop growth. In order to provide nutrient management guidelines for users of VC amended container substrates, a study was conducted to quantify nutrients supplied to substrates solution and to develop nutrient release kinetic models to predict plant available nutrient based on total initial loading rates. Experimental treatments and results were expressed on a volume basis (4-L container) for easy interpretation and application by growers of crops in containers.}, number={2}, journal={Compost Science & Utilization}, author={McGinnis, M. S. and Wagger, M. G. and Warren, S. L. and Bilderback, T. E.}, year={2010}, pages={97–104} }
 @article{burns_wagger_fisher_2009, title={Animal and Pasture Productivity of 'Coastal' and 'Tifton 44' Bermudagrass at Three Nitrogen Rates and Associated Soil Nitrogen Status}, volume={101}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2008.0006x}, abstractNote={‘Coastal’ and ‘Tifton 44’ (T44) bermudagrass [Cynodon dactylon (L.) Pers.] are well adapted across the lower southern United States, but the grazing response of (T44) to N application in the Piedmont of the upper South warrants further evaluation. This 3‐yr experiment compared animal and pasture productivity of Coastal and T44 with three annual N rates of 101, 202, and 303 kg of N ha−1 on a Cecil clay loam (fine, kaolinitic thermic Typic Kanhapludult) soil typical of the Piedmont. Herbage mass differed for Coastal and T44 (3.5 and 3.0 Mg ha−1 respectively, P < 0.01), but not among N rates. The canopy of T44 was leafier (20.6 vs. 14.5% of dry matter) than Coastal and greater for in vitro true organic matter disappearance (IVTOD) (522 vs. 498 g kg−1) and CP (107 vs. 84 g kg−1) and lesser in NDF (596 vs. 605 g kg−1). The diet selected from T44 was greater in IVTOD (764 vs. 743 g kg−1) and lesser in NDF (596 vs. 605 g kg−1) giving greater steer average daily gain (0.63 kg vs. 0.57 kg; P < 0.01) which increased (P = 0.05) with N rate. Weight gain ha−1 (884 kg) and effective feed units (EFU) (4735 kg ha−1) were similar, and N rate linearly increased gain from 723 to 1073 kg ha−1 and EFU from 3978 to 5523 kg ha−1. Soil inorganic N was similar between cultivars but differed among soil depths. Tifton 44 pasture was greater in nutritive value, hence steer performance, and as productive as Coastal in the Piedmont.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Wagger, M. G. and Fisher, D. S.}, year={2009}, pages={32–40} }
 @article{finney_creamer_schultheis_wagger_brownie_2009, title={Sorghum sudangrass as a summer cover and hay crop for organic fall cabbage production}, volume={24}, ISSN={["1742-1713"]}, DOI={10.1017/S174217050999007X}, abstractNote={Abstract}, number={3}, journal={RENEWABLE AGRICULTURE AND FOOD SYSTEMS}, author={Finney, Denise M. and Creamer, Nancy G. and Schultheis, Jonathan R. and Wagger, Michael G. and Brownie, Cavell}, year={2009}, month={Sep}, pages={225–233} }
 @article{afyuni_wagger_2006, title={Soil physical properties and bromide movement in relation to tillage system}, volume={37}, ISSN={["1532-2416"]}, DOI={10.1080/00103620500449393}, abstractNote={Abstract Conventional (CT) and no‐tillage (NT) effects on soil physical properties and bromide (Br) movement were studied at two locations in North Carolina. The soils were a Norfolk sandy loam (fine‐loamy, siliceous, thermic Typic Paleudult) at a North American eastern Coastal Plain location and a Pacolet sandy clay loam (clayey, kaolinitic, thermic Typic Kanhapludult) at a Piedmont location. Bulk density (Db), macroporosity (Mp), and saturated hydraulic conductivity (Ks) were measured in the plant row (R) and trafficked (T) or untrafficked (N) interrow positions. Simulated rain was applied at two intensities to 1−m2 plots after KBr was surface applied. The first simulated rain (30 min) consisted of a low (1.27 cm h−1) or a high (5.08 cm h−1) intensity applied 24 h after Br application. One week later, the high rainfall rate was repeated on all plots. Soil samples for Br determinations were taken 2 days after each rain simulation event to a depth of 40 cm and at the end of the growing season to 120 cm. Soil physical properties were affected by both tillage and position. Bulk density was greater for NT than for CT and in the T compared with R and N row positions. Mp was significantly greater in NT than CT at Coastal Plain location, but the results were opposite at the Piedmont location. Saturated hydraulic conductivity was highly variable ranging from 0.36 cm h−1 to 14.4 cm h−1 at the Coastal Plain location and from 0.06 cm h−1 to 7.12 cm h−1 at the Piedmont location. Saturated hydraulic conductivity at T position was about 100% lower than Ks at N and R positions, but the effect of tillage system was not significant on Ks. The surface 10 cm of soil contained the greatest Br concentration for both tillage systems. For the first and second sampling dates, greater Br movement occurred under NT vs. CT. However, no significant differences were observed in Br movement in the end of season sampling. Because of the coarser soil texture, greater Ks and Mp at the Coastal Plain location, Br moved, to a greater depth at this site than at the Piedmont site.}, number={3-4}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Afyuni, M and Wagger, MG}, year={2006}, pages={541–556} }
 @article{soto_luna-orea_wagger_smyth_alvarado_2005, title={Foliage residue decomposition and nutrient release in peach palm (Bactris gasipaes Kunth) plantations for heart-of-palm production in Costa Rica}, volume={97}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2004.0250}, abstractNote={Peach palm (Bactris gasipaes Kunth) for heart‐of‐palm production exports relatively low amounts of nutrients from the field and leaves considerable amounts of residue and nutrients on the ground as mulch. The primary objective of this study was to gain an understanding of residue decomposition and nutrient release patterns of peach palm foliage in a mature plantation in Costa Rica. The study was conducted within a 16‐yr commercial peach palm stand during two typically seasonal wet periods and one typically dry period. The third leaf of the five leaves cut during harvest of the stem portion were placed in 1‐mm mesh nylon bags. Bags were placed on the soil surface and retrieved at 1, 2, 4, 8, 16, 24, 32, 40, and 48 wk. Initial residue N concentrations over the three placement periods ranged from 24.2 to 28.1 g kg−1, C to N ratios between 16:1 and 17:1, cellulose from 251 to 325 g kg−1, and lignin from 80 to 104 g kg−1. There was no effect of seasonal periods on residue decomposition and N, P, and K release. Residue decomposition and nutrient release were best fitted by single‐exponential, three‐parameter models. The residue decomposition rate was 0.1472 wk−1 while nutrient release rates ranged from 0.0297 to 0.2998 wk−1. The potentially available nutrient pools in 4‐ and 8‐yr peach palm stands from a companion experiment ranged on an annual basis from 93 to 107 kg N ha−1, 14 to 15 kg P ha−1, 90 to 116 kg K ha−1, 19 to 23 kg Ca ha−1, and 13 to 14 kg Mg ha−1. The relatively rapid decomposition and nutrient release rates would seem to be ideal for this perennial cropping system where plants are continuously absorbing nutrients during the year to support the growth of offshoots that eventually become harvestable stems.}, number={5}, journal={AGRONOMY JOURNAL}, author={Soto, G and Luna-Orea, P and Wagger, MG and Smyth, TJ and Alvarado, A}, year={2005}, pages={1396–1402} }
 @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{njunie_wagger_luna-orea_2004, title={Residue decomposition and nutrient release dynamics from two tropical forage legumes in a Kenyan environment}, volume={96}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2004.1073}, abstractNote={Soil fertility decline is one of the factors limiting food production on the east coast of Africa. Increased awareness by smallholder farmers of the role of legumes as sources of food and fodder and for soil fertility improvement has stimulated research on the influence of herbaceous legumes in various cropping systems. Decomposition and nutrient release from foliage of legume species clitoria (Clitoria ternatea L.) and dolichos (Lablab purpureus L.) planted in monoculture and as an intercrop with tropical food crops cassava (Manihot esculenta Crantz) and maize (Zea mays L.) were evaluated under field conditions in fine‐loamy, kaolinitic, isohyperthermic, arenic Paleustalfs. The nylon mesh bag technique was used to obtain data to calculate the residue decomposition and nutrient release rates of the clitoria foliage cut every 6 or 10 wk and dolichos foliage cut at 2 or 4 mo. Asymptotic models provided the best fit for both dry matter decomposition and nutrient release. Legume residue decomposition rates (k) were unaffected by cropping system, with values of 0.2 and 0.5 wk−1 for clitoria and dolichos, respectively. Across cutting management strategies, the general order of nutrient release for clitoria at 6 or 10 wk was K > P > Mg > N; while that of dolichos was K > Mg > P > N and K > P > Mg > N for cuts at 2 and 4 mo, respectively. Overall, the residue N, P, and Mg release curves became asymptotic shortly after 60% of the nutrients had been released. Clitoria and dolichos showed their potential to become sources of nutrients for associated crops while protecting the soil surface.}, number={4}, journal={AGRONOMY JOURNAL}, author={Njunie, MN and Wagger, MG and Luna-Orea, P}, year={2004}, pages={1073–1081} }
 @article{glasener_wagger_mackown_volk_2002, title={Contributions of shoot and root nitrogen-15 labeled legume nitrogen sources to a sequence of three cereal crops}, volume={66}, ISSN={["0361-5995"]}, DOI={10.2136/sssaj2002.0523}, abstractNote={Legume mulches are important sources of N for cereal crop production, particularly for organic and resource-poor producers. A field study was conducted using a direct method to determine if the amount of N in cereal crops derived from either the shoots or roots of preceding tropical legume cover crops was affected by their chemical composition and mineralization potential. Desmodium ovalifolium Guill. & Perr. [= D adscendens (Sw.) DC. and Pueraria phaseoloides (Roxb.) Benth.], were grown in 6.0-m2 microplots and foliar-labeled with 99 atom % 15N urea. A cereal sequence of maize (Zea mays L.)–rice (Oryza sativa L.)–maize followed the legumes. Cereal accumulation of legume N from either the shoot (shoot + leaf litter) or the root-soil sources was evaluated by spatially separating the legume N sources. This was achieved by interchanging surface applications of nonlabeled and 15N-labeled legume shoots with in situ 15N-labeled and nonlabeled legume roots. Initially the Desmodium shoot N source contained 316 kg N ha−1 and roots contained 12.5 kg N ha−1 Pueraria shoots and root N sources initially contained 262 and 14.8 kg N ha−1, respectively. About 90 g kg−1 of the initial N of each legume shoot was recovered in the total aboveground tissues from the three cereal crops, while 490 g kg−1 of Desmodium and 280 g kg−1 of Pueraria root-soil N sources were recovered. Of the 181 kg N ha−1 accumulated aboveground by the cereal sequence, the contribution of shoot plus root-soil N sources was 200 g kg−1 from Desmodium and 150 g kg−1 from Pueraria Cereal N was derived primarily from mineralization of soil organic matter present before the legumes and possibly from N deposition (precipitation and dry) occurring during the cereal crop sequence. After harvest of the last cereal crop, 13 and 180 g kg−1 of the initial legume N was present as inorganic and organic N fractions, respectively, in the top 75 cm of soil. Even though Pueraria shoots had a lower C:N ratio and concentration of polyphenols than Desmodium shoots, the relative contributions of the shoot N source were similar for both legumes. Decomposition of legume residues, particularly legume shoots, make a meaningful contribution to the N economy of cereal crops grown in the tropics. The legume cover crops (root + shoot) contributed nearly 280 g kg−1 of the aboveground N in the first cereal crop and as much as 110 g kg−1 of the N in the third crop during the 15-mo sequence of cereals.}, number={2}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Glasener, KM and Wagger, MG and MacKown, CT and Volk, RJ}, year={2002}, pages={523–530} }
 @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{wagger_cabrera_ranells_1998, title={Nitrogen and carbon cycling in relation to cover crop residue quality}, volume={53}, number={3}, journal={Journal of Soil & Water Conservation}, author={Wagger, M. G. and Cabrera, M. L. and Ranells, N. N.}, year={1998}, pages={214–218} }
 @article{glasener_wagger_mackown_volk_1998, title={Nitrogen-15 labeling effectiveness of two tropical legumes}, volume={200}, ISSN={["1573-5036"]}, DOI={10.1023/A:1004330514833}, number={2}, journal={PLANT AND SOIL}, author={Glasener, KM and Wagger, MG and MacKown, CT and Volk, RJ}, year={1998}, month={Mar}, pages={149–156} }
 @article{ranells_wagger_1997, title={Grass-legume bicultures as winter annual cover crops}, volume={89}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1997.00021962008900040019x}, abstractNote={Abstract}, number={4}, journal={AGRONOMY JOURNAL}, author={Ranells, NN and Wagger, MG}, year={1997}, pages={659–665} }
 @article{ranells_wagger_1997, title={Nitrogen-15 recovery and release by rye and crimson clover cover crops}, volume={61}, ISSN={["0361-5995"]}, DOI={10.2136/sssaj1997.03615995006100030033x}, abstractNote={Abstract}, number={3}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Ranells, NN and Wagger, MG}, year={1997}, pages={943–948} }
 @article{afyuni_wagger_leidy_1997, title={Runoff of two sulfonylurea herbicides in relation to tillage system and rainfall intensity}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600050018x}, abstractNote={Abstract}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Afyuni, MM and Wagger, MG and Leidy, RB}, year={1997}, pages={1318–1326} }
 @article{ranells_wagger_1997, title={Winter annual grass-legume bicultures for efficient nitrogen management in no-till corn}, volume={65}, ISSN={["0167-8809"]}, DOI={10.1016/S0167-8809(97)00054-6}, abstractNote={Winter annual cover crops may be an effective tool for managing inorganic N in the sandy soils of the Atlantic Coastal Plain when summer droughts can result in relatively high residual fertilizer N levels. A field experiment was conducted from 1992 to 1994 on a Norfolk loamy sand to determine the effect of (1) previous corn fertilizer N rate (150 or 300 kg ha−1) on dry matter (DM) and N accumulation in rye, crimson clover, and hairy vetch monocultures and respective rye-legume bicultures; (2) the respective cover crops on residual soil inorganic N levels; and (3) cover crops on corn grain yield. Compared to the preplant corn N rate of 150 kg ha−1, the 300 kg N ha−1 rate resulted in greater profile soil inorganic N contents on subsequent sampling dates in both years. Concomitant with these greater residual soil N levels were increases in cover crop DM and N accumulation compared with low residual soil N levels. Averaged over 2 year, cover crop DM accumulation by April was in the order of rye > rye-vetch = rye-crimson clover > hairy vetch > crimson clover. The corresponding cover crop N content ranking was hairy vetch > rye-hairy vetch > crimson clover = rye-crimson clover > rye. Before corn planting in Apr, rye monoculture reduced soil inorganic N content an average of 62% in 1993 and 37% in 1994 compared to legume monocultures. Soil inorganic N content under the rye-legume bicultures was reduced an average of 44% and 15% for the same dates. Inadequate rainfall during both corn growing seasons resulted in poor corn yields (1.18 to 2.50 Mg ha−1) that were generally unaffected by cover crop or prior N rate. The results from this study demonstrated the ability of rye and rye-legume bicultures to scavenge residual soil inorganic N following a summer corn crop, thereby minimizing the leaching of N from the plant rooting zone.}, number={1}, journal={AGRICULTURE ECOSYSTEMS & ENVIRONMENT}, author={Ranells, NN and Wagger, MG}, year={1997}, month={Oct}, pages={23–32} }
 @article{wagger_cassel_1993, title={CORN YIELD AND WATER-USE EFFICIENCY AS AFFECTED BY TILLAGE AND IRRIGATION}, volume={57}, ISSN={["0361-5995"]}, DOI={10.2136/sssaj1993.03615995005700010040x}, abstractNote={Water is the main factor limiting row crop production in the southeastern USA. The objective of this study was to evaluate the effects of three irrigation regimes and two tillage systems on corn (Zea mays L.) production and water-use efficiency in the North Carolina Piedmont. An experiment was conducted on a Hiwassee clay loam (clayey, kaolinitic, thermic Rhodic Kanhapludult) from 1986 through 1989. Tillage treatments were conventional tillage (CT) and no-tillage (NT) in factorial combination with the following irrigation treatments: (i) full, where plots received 2.5 cm of water beginning 5 wk after planting when soil water pressure decreased to −60 kPa at 30 cm; (ii) limited, where 2.5-cm of water was applied according to the criterion above, but only from 2 wk before tasseling to 2 wk after silking; and (iii) dryland, no irrigation. The first 3 yr were drier, and 1989 was slightly wetter, than normal. Grain and silage yields were significantly different for irrigation and tillage each year, except for grain in 1986. Mean 4-yr grain yields were 4.45 Mg ha−1 for dryland, 8.00 Mg ha−1 for limited, and 10.77 Mg ha−1 for full irrigation. The mean 4-yr grain yield for CT was 7.47 Mg ha−1, compared with 8.01 Mg ha−1 for NT. Water-use efficiency for corn grain was similar for both tillage treatments, being 217 kg ha−1 cm−1 of applied irrigation water; for silage, water-use efficiency was 277 kg ha−1 cm−1 for CT compared with 381 kg ha−1 cm−1 for NT. These results indicate the potential for irrigation in Piedmont areas with limited water supplies when used in conjunction with the soil-water-conserving aspect of a NT system.}, number={1}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={WAGGER, MG and CASSEL, DK}, year={1993}, pages={229–234} }
 @article{wagger_vepraskas_denton_1992, title={CORN GRAIN-YIELD AND NITROGEN-UTILIZATION IN RELATION TO SUBSOILING AND NITROGEN RATE ON PALEUDULTS}, volume={84}, ISSN={["1435-0645"]}, DOI={10.2134/agronj1992.00021962008400050023x}, abstractNote={Abstract}, number={5}, journal={AGRONOMY JOURNAL}, author={WAGGER, MG and VEPRASKAS, MJ and DENTON, HP}, year={1992}, pages={888–892} }