Seshadri Sajjala Reddy, Chandra Reddy, and Tiffany Roberson. Alabama A&M University, Department of Plant and Soil Sciences, Normal, AL 35762
Carbon dioxide, a potential green house gas is released from soil to the atmosphere during and after various agricultural operations. A long-term study is being conducted at Belle Mina, Alabama to identify the appropriate management practices that could reduce the release of carbon dioxide from the soil. The study was initiated in 1996 on a Decatur silt loam (clayey, kaolinitic thermic, Typic Paleudults) to study the effect of different tillage systems (conventional-tillage (CT), mulch-tillage (MT), and no-tillage (NT)) with winter rye [Secale cereale (L.)] cover cropping and poultry litter as a nitrogen source in rotation with corn (Zea mays) on soil quality. Since 2003, CO2 efflux measurements have been taken using LI-COR 6400 Infrared Gas Analyzer (LI-COR, Lincoln, NE) in conjunction with LI-09 soil chamber to study the treatments’ effect on carbon sequestration in the soil. Measurements were taken at 7-day intervals from pre-planting till harvest of the crops. Initial data analyses indicate that CO2 efflux during the cotton growing season in NT plots (2.7 and 2.4 μmol m-2 s-1 in 2003 and 2004, respectively) was significantly lower than that in CT (4.4 and 2.8 μmol m-2 s-1 ) and MT ( 3.8 and 3.2 μmol m-2 s-1 ) plots. On average, plots receiving poultry litter released 18% more CO2 than those receiving ammonium nitrate, yet, increased soil carbon levels by 11%. Our study suggests that NT conservation tillage system in conjunction with poultry litter application at the rate of 100 or 200 kg N ha-1 promotes carbon storage in soil.