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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #341383

Research Project: Development of Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research

Title: Cover crop and nitrogen fertilization influence soil carbon and nitrogen under bioenergy sweet sorghum

Author
item Sainju, Upendra
item SINGH, HARI - Fort Valley State University
item SINGH, BHARAT - Fort Valley State University
item WHITEHEAD, WAYNE - Fort Valley State University
item CHILUWAL, ANUJ - Kansas State University
item PAUDEL, RAJESH - Tribhuvan University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2017
Publication Date: 3/1/2018
Publication URL: http://handle.nal.usda.gov/10113/5922765
Citation: Sainju, U.M., Singh, H.P., Singh, B.P., Whitehead, W.F., Chiluwal, A., Paudel, R. 2018. Cover crop and nitrogen fertilization influence soil carbon and nitrogen under bioenergy sweet sorghum. Agronomy Journal. 110(2):463-471. https://doi.org/10.2134/agronj2017.05.0253 .
DOI: https://doi.org/10.2134/agronj2017.05.0253

Interpretive Summary: Sweet sorghum is a promising bioenergy crop because of its high sugar content and its multiple uses of lignocellulose, starch, and bagasse for ethanol production. Extensive removal of aboveground biomass for bioenergy production, however, can affect soil and environmental quality. Winter cover crops and nitrogen fertilization can provide additional crop residues and carbon and nitrogen inputs that may help to protect soil and environmental quality. The effect of winter cover crops (hairy vetch, rye, hairy vetch/rye mixture, and the control [no cover crop]) and nitrogen fertilization rates (0 and 90 kg N ha-1) were evaluated on soil organic carbon, total nitrogen, ammonium-nitrogen, and nitrate-nitrogen contents at the 0- to 30-cm depth from 2010 to 2014 in the southeastern USA. Cover crop biomass yield and carbon content were greater with vetch/rye than vetch and the control and N content was greater with vetch and vetch/rye than with the control in 2013 and 2014. Soil organic carbon and total nitrogen at 0 to 5 cm were greater with vetch/rye than the control and at 15 to 30 cm were greater with vetch than vetch/rye. At 0 to 5 cm, soil organic carbon increased at 0.55 Mg C ha-1 yr-1 and total nitrogen at 0.06 Mg C ha-1 yr-1, regardless of treatments. At most depths, ammonium-nitrogen content was greater with rye than the control and greater with 0 than 90 kg N ha-1. Nitrate-nitrogen was greater with vetch/rye than rye. Because of greater cover crop carbon and nitrogen inputs, soil organic carbon, total nitrogen, and nitrate-nitrogen contents increased with vetch/rye and vetch alone compared to rye and the control, but ammonium-nitrogen content increased with rye. Soil carbon and nitrogen stocks can be enhanced and nitrogen availability can be optimized by growing hairy vetch alone or a hairy vetch plus rye mixture compared with other cover crops in a bioenergy sweet sorghum croppying system.

Technical Abstract: Cover crop and N fertilization may maintain soil C and N levels under sweet sorghum (Sorghum bicolor [L.] Moench) biomass harvested for bioenergy production. The effect of cover crops (hairy vetch [Vicia villosa Roth], rye [Secaele cereale L.], hairy vetch/rye mixture, and the control [no cover crop]) and N fertilization rates (0 and 90 kg N ha-1) were evaluated on soil organic C (SOC), total N (STN), NH4-N, and NO3-N contents at the 0- to 30-cm depth from 2010 to 2014 in the southeastern USA. Cover crop biomass yield and C content were greater with vetch/rye than vetch and the control and N content greater with vetch and vetch/rye than the control in 2013 and 2014. The SOC and STN at 0 to 5 cm were greater with vetch/rye than the control and at 15 to 30 cm were greater with vetch than vetch/rye. At 0 to 5 cm, SOC increased at 0.55 Mg C ha-1 yr-1 and STN at 0.06 Mg C ha-1 yr-1, regardless of treatments. At most depths, NH4-N content was greater with rye than the control and greater with 0 than 90 kg N ha-1, but NO3-N content was greater with vetch/rye than rye. Because of greater cover crop C and N inputs, SOC, STN, and NO3-N contents increased with vetch/rye and vetch than rye and the control, but NH4-N content increased with rye. Soil C and N stocks can be enhanced and N availability can be optimized by growing hairy vetch and rye mixture.