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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #340691
Title: Soil carbon and nitrogen under bioenergy forage sorghum influenced by cover crop and nitrogen fertilization

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

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2018
Publication Date: 7/2/2018
Citation: Sainju, U.M., Singh, H.P., Singh, B.P., Chiluwal, A., Paudel, R. 2018. Soil carbon and nitrogen under bioenergy forage sorghum influenced by cover crop and nitrogen fertilization. Agrosystems, Geosciences & Environment. 1:180004. https://doi.org/10.2134/age2018.03.0004.
DOI: https://doi.org/10.2134/age2018.03.0004

Interpretive Summary: Bioenergy crops, such as forage sorghum, have the potential to produce large cellulosic feedstock that can address the shortage of the biofuel demand because of their high aboveground biomass yields. Extensive removal of aboveground biomass for bioenergy, however, can reduce soil and environmental quality. Information is limited about the effect of crop residue removal on soil carbon and nitrogen storage and nitrogen leaching under bioenergy crops. We evaluated the effects of cover crops (hairy vetch, rye, hairy vetch/rye mixture, and the control [no cover crop]) and N fertilization rates (0 and 90 kg N ha-1) on soil organic carbon, total N, ammonium-nitrogen, and nitrate-nitrogen at the 0- to 30-cm depth from 2010 to 2014 in the southeastern USA. Cover crop biomass yield and carbon and nitrogen contents were greater with vetch/rye than rye and the control in 2013 and 2014. At 0-5 and 0-30 cm, soil organic carbon was greater with vetch/rye than rye and vetch and soil total nitrogen greater with vetch and vetch/rye than the control at 0 kg N ha-1. At 0-30 cm, soil organic carbon increased at 2.62 Mg C ha-1 yr-1 and soil total N at 0.35 Mg N ha-1 yr-1 with vetch/rye compared to nonsignificant increases with other cover crops from 2010 to 2014. The ammonium-nitrogen at 5-15 cm was greater with rye than other cover crops in 2012 and nitrate-nitrogen content at 5-15 and 0-30 cm was greater with vetch and vetch/rye than rye and the control in 2011 and 2012. Because of increased carbon and nitrogen inputs, soil organic carbon, total nitrogen, and nitrate-nitrogen contents increased with vetch/rye and vetch than rye and the control, but nitrogen fertilization had little effect on soil carbon and nitrogen under forage sorghum. As a result, hairy vetch/rye mixture cover crop can be used to enhance soil carbon and nitrogen stocks and both hairy vetch and hairy vetch/rye can be used to optimize nitrogen availability to forage soghum.

Technical Abstract: Little is known about the effects of cover crop and N fertilization on soil C and N under forage sorghum (Sorghum vulgare Pers.) used for feedstock or bioenergy production. We examined the effects 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) 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 and N contents were greater with vetch/rye than rye and the control in 2013 and 2014. At 0-5 and 0-30 cm, SOC was greater with vetch/rye than rye and vetch and STN greater with vetch and vetch/rye than the control at 0 kg N ha-1. At 0-30 cm, SOC increased at 2.62 Mg C ha-1 yr-1 and STN at 0.35 Mg N ha-1 yr-1 with vetch/rye compared to nonsignificant increases with other cover crops from 2010 to 2014. The NH4-N content at 5-15 cm was greater with rye than other cover crops in 2012 and NO3-N content at 5-15 and 0-30 cm was greater with vetch and vetch/rye than rye and the control in 2011 and 2012. Because of increased C and N inputs, SOC, STN, and NO3-N contents increased with vetch/rye and vetch than rye and the control, but N fertilization had little effect on soil C and N under forage sorghum.