Using a chisel plow during fall tillage will maintain surface residue and minimize soil disturbance, which in turn will reduce carbon dioxide loss, according to Agricultural Research Service scientists in Auburn, Ala.

Plant Physiologist Stephen A. Prior and Agricultural Engineer Randy L. Raper of the ARS National Soil Dynamics Laboratory at Auburn are studying CO2 loss and how it relates to the farm equipment used and the time of year tillage takes place. While some CO2 always escapes to the atmosphere, losing too much of it during tillage may hurt the environment and can reduce soil productivity.

The scientists looked at loamy sand soil in east-central Alabama to see how much CO2 escaped due to the plowing of a grain sorghum field.

Disking caused more CO2 release than chisel plowing, because greater soil disturbance results from disking. Plots of land that were not tilled had low levels of CO2 loss, similar to those of fields that were chisel plowed.

Reduced CO2 loss was also found in plots where tillage was delayed until the spring. Leaving the crop residue in place over the winter months and postponing tillage until spring slows residue decomposition and protects the soil during winter rains.

ARS is the U.S. Department of Agriculture's chief scientific research

agency.