Influence of gypsum and cover crop on greenhouse gas emissions in soybean cropping systems

Authors: Watts, Dexter; Runion, George; DICK, WARREN - The Ohio State University; Gonzalez, Javier; ISLAM, KHANDAKAR - The Ohio State University; Flanagan, Dennis; Fausey, Norman; Vantoai, Tara; BATTE, MARVIN - The Ohio State University; REEDER, RANDALL - The Ohio State University; KOST, DAVID - The Ohio State University; CHEN, LIMING - The Ohio State University; JACINTHE, PIERRE-ANDRE - The Ohio State University

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2022
Publication Date: 2/6/2023
Citation: Watts, D.B., Runion, G.B., Dick, W., Gonzalez, J.M., Islam, K., Flanagan, D.C., Fausey, N.R., Vantoai, T.T., Batte, M., Reeder, R., Kost, D., Chen, L., Jacinthe, P. 2023. Influence of gypsum and cover crop on greenhouse gas emissions in soybean cropping systems. Journal of Soil and Water Conservation. 78(2):154-162. https://doi.org/10.2489/jswc.2023.00042.
DOI: https://doi.org/10.2489/jswc.2023.00042

Interpretive Summary: Agricultural farming practices can reduce greenhouse gas emissions and potentially limit climate change by improving carbon storage. In recent years, interest in the use of gypsum as a soil amendment for growing agricultural crops has increased. Presently, there is little information known on how gypsum influences greenhouse gas emission when used alone or with other common farming practices. A study was conducted at three locations (Indiana, Ohio and Alabama) across the US to evaluate the influence that gypsum and cover crops may have on greenhouse gas emissions (carbon dioxide, methane, and nitrous oxide) under two common soybean cropping systems (continuous soybeans and soybeans rotated with corn). Overall, greenhouse gas emissions were low throughout the study with the addition of gypsum, use of a rye cover crop, or crop rotations having minimal influence on gas loss. This was like due to the farming practices evaluated in this study having minimal fertilizer inputs.

Technical Abstract: Agriculture has the opportunity to mitigate anthropogenic contributions to global change by increasing soil sequestration of greenhouse gases (GHG) and by reducing efflux through management. Common agricultural management practices include crop rotation and use of cover crops. Interest in the use of gypsum in agricultural systems has also increased in recent years. However, little is known regarding how combining gypsum with other management practices will impact GHG emissions in soybean cropping systems. A study was implemented at three locations (i.e., east-central Indiana, northwest Ohio, and east-central Alabama) to evaluate the influence of gypsum and cover cropping within a continuous soybean and a corn (Zea mays L.)-soybean (Glycine max L.) rotation on GHG efflux. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) were monitored periodically following soybean seeding through harvest from 2012 to 2016 using a static chamber method. The combined gas data were then used to calculate a global warming potential (GWP). Overall, few differences in GHG emissions were observed across sites and years, and no consistent patterns were noted, likely due to large variabilities in gas efflux measurements and limited influence of treatments on trace gases. However, within specific years and at specific sites, treatment differences were observed for one or more GHG. Comparison across sites revealed the warmer/wetter climate in Alabama resulted in higher CO2 efflux, while higher soil organic matter at the northern sites led to higher N2O efflux. At all sites, CH4 was generally low and sites tended to be small net sinks. Given that GHG emissions drive GWP, it also showed few responses to treatments and no consistent patterns. It can be concluded from this study that gypsum and cover crop will likely have little influence on contributions of soybean cropping systems to global climate change.