Soil Surface Greenhouse Gas Flux for Differing Residue Removal Rates in a Corn-Soybean.

Agriculture is responsible for larger amount of soil surface greenhouse gases. This is attributed to the various land management practices involved with raising crops like fertilizer applications, tillage practices and crop residue management. It is important for agriculture to move towards more sustainable practices, ones that mitigate greenhouse gas emissions. This study was conducted to monitor greenhouse gas fluxes from a corn-soybean rotation that is under different rates of residue removal. The experimental site was located in Brookings County, South Dakota (SD) at the USDA-ARS North Central Agricultural Research Laboratory on a silty clay loam soil. The treatments included: two different residue removal rates: low residue removal (LRR), and high residue removal (HRR), and cover crop and no cover crop. The LRR treatment consisted of harvesting only the corn grain, leaving all other plant materials on the soil surface, and the HRR consisted of cutting the stalks 0.15 m from the ground and removing that portion of the plant. Data collected in the summer of 2013 show that CO₂ is responsive to temperature. Spikes in flux were observed with spikes in daily temperature. N₂O fluxes were observed to be more responsive to changes in soil moisture. Spikes in flux were notices after rainfall events and after fertilization events. The LRR treatment showed to have higher N₂O fluxes during this time, while the HRR treatment showed to have higher CO₂ fluxes.