Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: July 26, 2002
Publication Date: November 4, 2002
Citation: SCHOMBERG, H.H., ALLMARAS, R.R., DOUGLAS JR, C.L., DAO, T.H. SOIL CARBON SEQUESTRATION POTENTIAL OF CONSERVATION TILLAGE SYSTEMS. AMERICAN SOCIETY OF AGRONOMY MEETINGS. 2002. Technical Abstract: This analysis of published data shows that because of increased and stabilized crop residue inputs, improved tillage/residue placement systems, and adoption of improved tillage systems, US cropland changed from a carbon (C) source to a C sink in the 1980s. Much of the US cropland reached a new low steady state of soil organic carbon (SOC) and C emission by the late 1940s due to long cropping history and extensive moldboard plow use. Tillage technologies developed to replace moldboard plow reduce SOC losses and in many cases increase levels of SOC. US adoption of conservation tillage increased from the 1970s to 1990s. Genetic improvements in crops and improved fertilizer availability increased crop residue production 15 to 100% and increased C available for return to soil for both aboveground and belowground components of major US crops. Because this occurred on significant acreage, US cropland should be considered a significant sink for atmospheric C and no longer a source. Other projections of potential sequestration based on a full implementation of management improvements indicate further research and extension efforts aimed at achieving these goals are needed.