@article{butler_ranells_franklin_poore_green_2008, title={Runoff water quality from manured riparian grasslands with contrasting drainage and simulated grazing pressure}, volume={126}, ISSN={0167-8809}, url={http://dx.doi.org/10.1016/j.agee.2008.02.004}, DOI={10.1016/j.agee.2008.02.004}, abstractNote={Globally,management ofgrazedriparian areasiscriticallyimportanttoagriculturalsustainabilityandenvironmentalquality.However,the potential impacts of riparian grazing management on water quality are not well-documented, particularly in the southeastern USA. The objective of this work was to determine sediment and nutrient export under simulated rainfall from poorly drained and well-drained riparian soils where heavy or light grazing pressure by cattle was simulated. Plots were established on stands of existing vegetation to create grazing pressure treatments of (a) light-use (full ground cover, uncompacted), and with stands modified to establish (b) heavy-use (bare ground, compacted) treatments. Vegetation on poorly drained soils consisted of several typical wetland species (e.g., Pontederia cordata L., Juncus coriaceus Mackenzie) in the southeastern USA, whereas mixed tall fescue (Festuca arundinacea Schreb.)‐dallisgrass (Paspalum dilatatum Poir.) stands were the dominant vegetation on well-drained soils. Runoff volumewas generally greater from heavy-use than from light-use for poorly drained soils and for well-drained soils. Greater runoff volume was also observed from poorly drained soils compared to well-drained soils for both light-use and for heavy-use treatments. Light-use plots were remarkably effective at minimizing export of total suspended solids (TSS)onboth soils (<30 kg ha � 1 ). Mean total Kjeldahl P(TKP) exportwas fourfold greater from heavy-useplots than from light-use plots on both soils. While export of nitrate-nitrogen (NO3-N) was unaffected by grazing pressure and soil drainage, mean ammonium-nitrogen (NH4N) and total N (TN) export from poorly drained heavy-use plots was greater than fivefold that from well-drained light-use plots. Results indicate that livestock heavy-use areas in the riparian zone may export substantial TSS and nutrients, especially on poorly drained soils. However, when full ground cover is maintained on well-drained soils, TSS and nutrient losses may be limited. # 2008 Elsevier B.V. All rights reserved.}, number={3-4}, journal={Agriculture, Ecosystems & Environment}, publisher={Elsevier BV}, author={Butler, David M. and Ranells, Noah N. and Franklin, Dorcas H. and Poore, Matthew H. and Green, James T., Jr.}, year={2008}, month={Jul}, pages={250–260} }
 @article{iyyemperumal_green_israel_ranells_shi_2008, title={Soil chemical and microbiological properties in hay production systems: residual effects of contrasting N fertilization of swine lagoon effluent versus ammonium nitrate}, volume={44}, ISSN={["1432-0789"]}, DOI={10.1007/s00374-007-0221-y}, number={3}, journal={BIOLOGY AND FERTILITY OF SOILS}, author={Iyyemperumal, Kannan and Green, James, Jr. and Israel, Daniel W. and Ranells, Noah N. and Shi, Wei}, year={2008}, month={Feb}, pages={425–434} }
 @article{butler_ranells_franklin_poore_green_2007, title={Ground cover impacts on nitrogen export from manured riparian pasture}, volume={36}, ISSN={["0047-2425"]}, DOI={10.2134/jeq2006.0082}, abstractNote={ABSTRACT Maintaining ground cover of forages may reduce the export of nitrogen (N) from pastures. The objective of this work was to determine the effect of ground cover on N export from pastured riparian areas receiving simulated rainfall. Plots were established on two adjacent sites in the North Carolina Piedmont: one of 10% slope with Appling sandy loam soils and a second of 20% slope with Wedowee sandy loam soils. Both sites had existing mixed tall fescue ( Festuca arundinacea Schreb.)‐dallisgrass ( Paspalum dilatatum Poir.) vegetation. Forage stands were modified to represent a range of ground cover levels: 0, 45, 70, and 95% (bare ground, low, medium, and high cover, respectively), and amended with beef steer ( Bos taurus ) feces and urine (∼200 kg N ha −1 ). For all rain events combined, mean nitrate N export was greatest from bare ground and was reduced by 34% at low cover, which did not differ from high cover. Mean ammonium N export was slightly elevated (∼1.37 kg N ha −1 ) in months when manures were applied and negligible (<0.02 kg N ha −1 ) in all other months. For all rain events combined, mean export of total N was greatest from bare ground and was reduced by at least 85% at all other cover levels. Whereas site did not impact N export, results indicated that cover and time of rainfall following manure deposition are important determinants of the impact of riparian grazing.}, number={1}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Butler, David M. and Ranells, Noah N. and Franklin, Dorcas H. and Poore, Matthew H. and Green, James T., Jr.}, year={2007}, pages={155–162} }
 @article{butler_franklin_ranells_poore_green_2006, title={Ground cover impacts on sediment and phosphorus export from manured riparian pasture}, volume={35}, DOI={10.2134/ieq2005.0351}, number={6}, journal={Journal of Environmental Quality}, author={Butler, D. M. and Franklin, D. H. and Ranells, N. N. and Poore, M. H. and Green, J. T.}, year={2006}, pages={2178–2185} }
 @article{reberg-horton_burton_danehower_ma_monks_murphy_ranells_williamson_creamer_2005, title={Changes over time in the allelochemical content of ten cultivars of rye (Secale cereale L.)}, volume={31}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-005-0983-3}, number={1}, journal={JOURNAL OF CHEMICAL ECOLOGY}, publisher={Springer Nature}, author={Reberg-Horton, SC and Burton, JD and Danehower, DA and Ma, GY and Monks, DW and Murphy, JP and Ranells, NN and Williamson, JD and Creamer, NG}, year={2005}, month={Jan}, pages={179–193} }
 @article{osmond_ranells_hodges_hansard_xu_jones_pratt_2002, title={Tracking nitrogen loading reductions from agricultural sources: NLEW}, ISBN={1901502787}, journal={Climate variability and change : hydrological impacts}, publisher={Wallingford, Oxfordshire, UK : International Association of Hydrological Sciences}, author={Osmond, D. L. and Ranells, N. N. and Hodges, S. C. and Hansard, R. and Xu, L. and Jones, T. E. and Pratt, S. H.}, editor={Demuth, S. and Askew, A.Editors}, year={2002} }
 @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{ranells_wagger_1997, title={Grass-legume bicultures as winter annual cover crops}, volume={89}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1997.00021962008900040019x}, abstractNote={Abstract Grass‐legume bicultures as winter annual cover crops may combine the N scavenging ability of grasses and the biological N 2 fixation capacity of legumes to improve N management in crop production systems of the southeastern USA. A 3‐yr field experiment was conducted on a Norfolk loamy sand (fine‐loamy, kaolinitic, thermic Typic Kandiudults). The focus of this research was to examine the differences among legume monocultures and grass‐legume bicultures with regard to early spring dry matter (DM) and N accumulation, and related effects on soil inorganic N levels and subsequent corn ( Zea mays L.) yield. Austrian winter pea [ Pisum sativum L. subsp, sativum var. arvense (L.) Poir.], crimson clover ( Trifolium incarnatum L.), commonve tch ( Vicla saava L.), and hairy vetch ( Vicla villosa Roth ) were grown in monoculture and in bicultures with rye ( Secale cereale L.), oat ( Arena satira L.), and wheat ( Triacum aestivum L.). Aboveground plant material was harvested in early March, late March, and mid‐April. Biomass was separated into component species and analyzed for total N and C concentrations. Averaged over 3 yr, legume component DM accumulation in monoculture and biculture ranged from 0.87 to 2.53 Mg ha −1 , with a ranking of Austrian winter pea < hairy vetch < commonv etch < crimson clover. For the same period, the grass component DM accumulation ranged from 1.31 to 2.28 Mg ha −1 , in the order rye = oat < wheat. Three‐year mean N accumulation values for the legume component followed the same relative ranking and ranged from 24 to 93 kg N ha −1 . Grass factor N content ranged from 18 to 39 kg N ha −1 in the order rye < oat < wheat. For all bicultures, the average C:N ratio over the 3‐yr experiment was >30, suggesting that net N mineralization would occur from the decomposing cover crop residues. Profile soil inorganic N (0 to 90 cm) was greater in legume monoculture than in grass‐legume biculture treatments, indicating the ability of grasses to capture soil N. Corn yield was affected by the treatments in 1 of 3 yr, with greater yields following a legume monoculture than a grass‐legume biculture. Collectively, these results suggest that grass‐legume bicultures as winter annual cover crops have the potential to utilize residual soil NO 3 and thereby minimize leaching while adding fixed N to cropping systems in the southeastern USA.}, 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 A grass‐legume biculture may be preferred over a legume monoculture cover crop due to the scavenging ability of a grass species, especially when high residual soil N levels are present following summer droughts in the Atlantic Coastal Plain. Rye ( Secale cereale L.) and crimson clover ( Trifolium incarnatum L.) were grown in monoculture and as a biculture in a 2‐yr field experiment on a Typic Kandiudult to assess cover crop recovery of fertilizer 15 N and the subsequent corn ( Zea mays L.) uptake of cover crop residue 15 N. Potassium nitrate labeled with 10 atom % 15 N was applied to microplots at 50 kg N ha ‐1 1 wk after seeding the cover crops, which were monitored for recovery of fertilizer 15 N. Labeled residue was placed in a new microplot to monitor release of residue 15 N and its recovery by corn. Averaged across both years, rye monoculture recovered 39% of the labeled 15 N fertilizer compared with 19% in the rye‐crimson clover biculture and 4% in the crimson clover monoculture. Following corn harvest and averaged across both years, total recovery of 15 N fertilizer from the original microplots (cover crop, corn biomass, and soil N) was 29% for crimson clover, 75% for rye, 55% for rye‐crimson clover biculture, and 20% for the native winter weeds. In 1993, corn recovery of residue 15 N was lowest in the rye monoculture (4%) compared with other treatments (20–35%). Results indicated that a rye‐crimson clover biculture was capable of recovering greater residual 15 N than a crimson clover monoculture, but less than rye monoculture.}, number={3}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Ranells, NN and Wagger, MG}, year={1997}, pages={943–948} }
 @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{ranells_wagger_1993, title={CRIMSON CLOVER MANAGEMENT TO ENHANCE RESEEDING AND NO-TILL CORN GRAIN PRODUCTION}, volume={85}, ISSN={["1435-0645"]}, DOI={10.2134/agronj1993.00021962008500010014x}, abstractNote={Abstract Economic savings and increased legume‐N use efficiency may result from natural reseeding of winter annual legume cover crops. A 3‐yr experiment was conducted on a Cecil fine sandy loam (clayey, kaolinitic, thermic Typic Kanhapludult) to examine the effects of crimson clover ( Trifolium incarnatum L.) strip desiccation width (25, 50, and 75% of row area) and orientation (parallel or perpendicular to plant row) on soil water depletion, corn ( Zea mays L.) growth and grain yield, and clover reseeding. Additional treatments included early desiccation (25% parallel strip 2 wk before corn planting), annual seeding (complete desiccation at corn planting), and mechanical disruption of clover growth by the no‐tillage planter. Early‐season soil water was lower in annual seeded plots compared to the 25% strip treatments each year, however, soil water was limiting in only one of 3 yr. Crimson clover successfully reseeded in all strip treatments each year, with dry matter production ranging from 3.0 to 5.2 Mg ha −1 in 1990 and from 3.9 to 5.2 Mg ha −1 in 1991. Nitrogen content of reseeded crimson clover biomass ranged from 86 to 134 kg ha −1 in 1990 and 93 to 111 kg ha −1 in 1991. Corn grain yield was only marginally affected by clover strip management in two out of 3 yr. Results suggest that under adequate moisture conditions a 50% desiccated strip has the potential to maximize clover N contribution. However, a 75% strip‐width can minimize potential competition with corn for water and reduce physical impedance of the clover cover crop on corn growth.}, number={1}, journal={AGRONOMY JOURNAL}, author={RANELLS, NN and WAGGER, MG}, year={1993}, pages={62–67} }
 @article{ranells_wagger_1993, title={CRIMSON CLOVER RESEEDING POTENTIAL AS AFFECTED BY S-TRIAZINE HERBICIDES}, volume={6}, ISSN={["0890-8524"]}, DOI={10.2134/jpa1993.0090}, abstractNote={Economic savings can result from allowing a crimson clover (Trifolium incarnatum L.) cover crop in no-tillage corn (Zea mays L.) systems to self-reseed and thereby eliminate the need for annual seeding operations. Research has indicated, however, that self-reseeding of crimson clover is variably sensitive to certain residual corn herbicides, depending on growth stage at time of herbicide application. Accordingly, a 2-yr experiment was conducted to evaluate the effects of atrazine, cyanazine, and simazine applied to crimson clover at four growth stages (late vegetative, early bloom, late bloom, and early seed set) on subsequent clover reseeding potential. All successfully reseeded crimson clover plots were sampled in 1990 and 1991 for dry matter (DM) and total N concentration []}, number={1}, journal={JOURNAL OF PRODUCTION AGRICULTURE}, author={RANELLS, NN and WAGGER, MG}, year={1993}, pages={90–93} }
 @article{ranells_wagger_1992, title={NITROGEN RELEASE FROM CRIMSON CLOVER IN RELATION TO PLANT-GROWTH STAGE AND COMPOSITION}, volume={84}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1992.00021962008400030015x}, abstractNote={Abstract Increased N‐use efficency and economic savings may result from a better understanding of N release patterns from legume residues. A 2‐yr field experiment was conducted on a Cecil fine sandy loam (clayey, kaolintic, thermic Typic Kanhapludult) to examine the effects of crimsom clover ( Trifolium incarnatum L.) growth stage on dry matter accumulation, N concentration, and chemical composition in relation to N release under no‐tillage management. Crimson clover was harvested in the spring at four growth stages (late vegetative, early bloom, late bloom, and early seed set). Air‐dried plant material in 1‐mm mesh nylon bags was placed on the soil surface; retreived at 1−, 2−, 4−, 8−, and 16‐wk intervals; and analyzed for total N, C, cellulose, hemicellulose, and lignin concentrations. Averaged over 2 yr, dry matter production increased from 2.3 to 5.6 Mg ha− 1 , and N concentration declined from 30.2 to 21.2 g kg− 1 as crimson clover matured from late vegetative to early seed set growth stages. Cellulose concentration increased by 66%, hemicellulose by 37%, and lignin by 87% from late vegetative to early seed set. Estimated clover N release at the 8‐wk retrieval was 28, 40, 40, and 54 kg ha− 1 in 1989 and 51, 67, 73, and 55 kg ha− 1 in 1990 for the late vegetative, early bloom, late bloom, and early seed set growth stages, respectively. Results indicated that allowing crimson clover to attain the late bloom stage prior to desiccation and planting of the summer crop can maximize clover top‐growth N content and subsequent N release.}, number={3}, journal={AGRONOMY JOURNAL}, author={RANELLS, NN and WAGGER, MG}, year={1992}, pages={424–430} }