Submitted to: National Conservation Tillage Digest
Publication Type: Trade Journal
Publication Acceptance Date: October 2, 1997
Publication Date: N/A
Technical Abstract: Agriculture's role in the global carbon balance needs to be understood to maintain environmental quality. Soil organic matter is the foundation of sustainable agriculture and is highly dependent on management decisions that influence the intensity of tillage and the amount and placement of residues. Tillage and soil carbon dioxide loss can contribute to potential climate change through the greenhouse effect. This review covers the importance of soil organic matter and recent research on short-term tillage-induced carbon dioxide losses related to tillage intensity, gas exchange was measured using a large portable closed chamber. The short-term losses of CO2 following moldboard plowing were large compared to the relatively small losses with no-till or conservation tillage. Moldboard plow was the most disruptive tillage treatment with most residue incorporation, greatest surface roughness, largest soil surface area and air spaces that all promoted carbon dioxide loss, compared to the plots no tilled. With conservation tillage, most crop residues are left on the soil surface, with only a small portion in intimate contact with soil moisture and available to microorganisms. The cumulative short-term CO2 loss for a conservation tillage tool was less than that of the moldboard plow. Large differences in CO2 loss between conventional tillage and no-tillage reflect the need for improved conservation tillage and residue management systems to enhance soil quality and promote carbon sequestration. Present data confirms how intensive tillage releases CO2, decreases soil carbon and supports increased adoption of new and improved forms of conservation tillage equipment that offers significant potential to preserve or increase soil C levels for enhanced environmental quality.