Effects of Cover Crops and Soil Amendments on Carbon Dioxide Emissions from Corn Cropping Systems in Mississippi

Hu, J., Lei, F., Miles, D. M., Adeli, A., Brooks, J. P., Smith, R., Podrebarac, F., Li, X., & Moorhead, R. J. (2021). Effects of Cover Crops and Soil Amendments on Carbon Dioxide Emissions from Corn Cropping Systems in Mississippi. ASA, CSSA, SSSA International Annual Meeting. Salt Lake City, UT: ASA-CSSA-SSSA.

Cover crops and soil organic amendments have been widely used in crop production systems to improve soil health, maximize crop yields and minimize adverse environmental effects. These practices would affect the soil biogeochemical processes and properties which are related to carbon dioxide (CO2) fluxes of the system. The objective of this study is to evaluate the CO2 fluxes from crop production systems with deep-rooted (bio-drilling) cover crops and soil amendments, including flue gas desulfurization gypsum, lignite, and broiler litter. A field study with a split-plot randomized block design was conducted in a corn production system at the Mississippi Agricultural and Forestry Experiment Station near Pontotoc. Fluxes of CO2 were measured in the field using LiCor 8100A every three weeks during the growing season. Our results showed that CO2 fluxes were significantly affected by soil amendment, time and their interaction (P < 0.001), but not by the cover crop. Cumulative fluxes during the growing season from plots subjected to broiler litter amendment were approximately 3.5 times higher than control and other soil amendments, which is possibly caused by the high content of labile organic carbon and inorganic nitrogen and phosphorus in the broiler litter. Peaks of CO2 flux (25-50 &Acirc;&micro;mol m-2 s-1) from broiler litter amended plots were observed in middle June, which are likely due to the proper soil temperature and water content which accelerated soil respiration when abundant carbon and nutrients were provided by broiler litter integration. The ongoing long-term study (in total 6 years) at this site would provide insights on changes in effects of cover crop and soil amendment on soil biogeochemical properties and greenhouse gas fluxes over time. Flux measurements out of the growing season should be included in future studies to provide us with a better understanding of the annual greenhouse gas and carbon budget.