Soil Carbon Dioxide Efflux Rates of Different Tillage Practices.

Global emissions of (CO₂)  the main cause of global warming- increased by 3% in 2011, reaching an all-time high of 34 billion tons in 2011 (Netherlands Environmental Assessment Agency, 2013 Report). Human induced increases in the atmospheric concentrations of greenhouse gases have been a concern over the past century, and are expected to drive climate change even in the coming decades. Soil is a major source of atmospheric CO₂. Soil contributes about 20% of the total emission of CO₂ to the atmosphere through soil respiration. In addition to disturbing the earth’s heat budget, emission of CO₂ from the soil can lead to a diminution of soil organic C pool, soil fertility and productivity. A field experiment was conducted at the Alabama A&M University Winfred Thomas Agricultural Research Station to investigate the effects of agronomic soil management practices on soil CO₂ emissions. The objectives of this study were: (1) to assess the impacts of tillage systems (conventional and conservation) on soil carbon dioxide emissions; and (2) to evaluate the relationships between soil CO₂ emissions and other soil properties such as soil water content, temperature and organic matter. An L1- 8100A portable soil CO₂ flux analyzer with eight chambers was deployed in tilled and no-tilled plots of winter wheat  and corn at the study site to continuously measure soil CO₂ emissions. Flux measurements of the tilled and no-tilled plots will indicate the effects of  tillage on soil CO₂ emissions. Soil CO₂ flux data for the winter wheat will also be compared with that of corn to evaluate the extent to which soil CO₂ emissions are affected by crop types.