ABSTRACT

Increased levels of carbon dioxide (CO₂) in the atmosphere could cause major changes in our global climate which could have a detrimental effect on world agriculture. More carbon (C) is contained in the soil than in the world’s atmosphere and vegetation combined, therefore soil organic matter (SOM) plays a vital role in the world carbon balance. A field study is being conducted using existing plots and treatments established in the Fall of 1996 in a cotton [Gossypium hirsutum (L.)] and corn (Zea mays) rotated field at the Alabama Agricultural Experiment Station, Belle Mina, AL. The objectives of this study are to measure, model, and document carbon sequestration and CO₂ loss in tilled and non-tilled cotton plots receiving poultry litter as a nutrient. In 2003, plots that received 100 kg poultry litter N ha^-1 had total carbon values in conventional-till (CT) which averaged 22 g/kg C. No significant differences due to treatments were found in the total carbon levels in the 0-5, and 60-90 cm layers of soil. Carbon dioxide efflux values in CT which averaged 5.6 um/m^-2/s^-1 were 9% higher than those in mulch till (MT), 83% higher than those in no-till (NT), and 307% higher than CO₂ efflux values in bare fallow (BF) plots. So far, this study demonstrates that no-till and mulch-till conservation tillage systems will sequester carbon by reducing the amount of CO₂ released from soils under cotton production. This will increase soil carbon, which will in turn increase soil productivity for sustainable agriculture.