ARS | Publication request: TILLAGE AS A MECHANISM FOR CO2 EMISSION FROM SOILS

Submitted to: Soil Source and Sink of Greenhouse Gases
Publication Type: Abstract Only
Publication Acceptance Date: September 21, 1995
Publication Date: N/A

Technical Abstract: The influence of agricultural production systems on greenhouse gas generation and emission is of interest as it may affect potential global climate change. Information is needed on the mechanism and magnitude of gas generation and emission from soils with specific emphasis on tillage mechanisms. This work evaluated different tillage methods on the short-term CO2 and water vapor flux from a clay loam soil in the Northern Cornbelt of the U.S.A. The four tillage methods were moldboard plow only, moldboard plow plus disk harrow twice, disk harrow and chisel plow using standard tillage equipment following a wheat (T. Aestivum L) crop compared with no tillage. The CO2 flux was measured with a large portable chamber commonly used to measure crop canopy gas exchange. The moldboard plow treatment buried nearly all of the residue and left the soil in a rough, loose, open condition and resulted in maximum CO2 loss. The carbon released as CO2 during the 19 days following the moldboard plow, moldboard plow plus disk harrow, disk harrow, chisel plow and not tilled treatments would account for 134%, 70%, 58%, 54% and 27% respectively of the carbon in the current years crop residue. Carbon dioxide losses 5 hours after four conservation tillage tools were only 31% of that of the moldboard plow. The moldboard plow lost 13.8 times as much CO2 as the soil area not tilled, while different conservation tillage tools lost only 4.3 times. Conservation tillage reduces the extent, frequency and magnitude of mechanical disturbance caused by the moldboard plow and reduces the air-filled macropores and slows the rate of carbon oxidation. Any effort to decrease tillage intensity and maximize residue return should result in carbon sequestration for enhanced environmental quality.