Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2007
Publication Date: 2/1/2007
Citation: Gacengo, C.N., Wood, C.W., Shaw, J.N., Balkcom, K.S., Raper, R.L. 2007. Effects of soil management and landscape factors on greenhouse gas emissions [abstract]. Southern Branch American Society of Agronomy Branch Annual Meeting. 2007 CDROM.
Technical Abstract: Soil management and landscape factors influence greenhouse gas emissions interactively rather than in isolation. Evaluation of effects of these factors and their interactions on greenhouse gas emissions is necessary for site specific management. This study evaluates effect of tillage, dairy manure application and landscape position on nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) emissions from a corn/cotton rotation farming system. Gas samples were collected using a closed chamber method near Shorter, AL in spring 2004. Treatments included no-till (NT) and conventional tillage (CT) with or without dairy manure application distributed over three landscape positions: concave, sideslope, and upland. Dairy manure increased CH4 emission while tillage decreased emissions. Concave positions recorded the highest CH4 emissions under both tillage systems while upland positions consumed CH4 (where no manure was applied). Tillage increased CO2 emission. Dairy manure decreased CO2 emission on sideslopes by 9% under CT and while it increased emissions by 20% under NT. Tillage increased N2O emission on all landscape positions with the increase being more pronounced on concave slopes. Dairy manure increased N2O emissions on concave zones under both tillage systems. Treatments on concave positions generally had higher emission of the three gases, and greater soil moisture in treatments without dairy manure application. Similar CO2 and N2O emissions were observed in summer and fall seasons, but during winter CT significantly decreased CO2 emission compared to NT. Adopting no-till in spring through fall can decrease CO2 and N2O emissions in agricultural systems. However, conventional tillage reduces CH4 emissions. Dairy manure application may convert upland landscapes from being CH4 sinks to CH4 sources. It is apparent that soil management and landscape position interact to control greenhouse gas emissions from agricultural fields. [GRACEnet Publication]