Submitted to: Advances in Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2000
Publication Date: N/A
Interpretive Summary: Conservation-tillage crop production has become an accepted practice throughout the USA and Canada. The Kyoto Protocol on climate change has prompted the agricultural sector to more seriously promote various forms of conservation tillage, including no tillage, as practices to help sequester carbon dioxide from the atmosphere into soil organic matter. Storage of carbon in soil can effectively reduce the buildup of carbon dioxide in the atmosphere, which has led to threats of global warming and climate change. We synthesized the results of long-term, no tillage experiments conducted in the USA and Canada in order to identify specific geographical regions with the greatest potential to store carbon in soil with adoption of no tillage. We found that a mild climatic zone located in the Midwest and Mid Atlantic states had the greatest potential to store additional carbon in soil by converting conventionally tilled cropland to no tillage.
Technical Abstract: No-tillage crop production (NT) is increasingly becoming an accepted practice throughout the USA and Canada. We synthesized available data on soil organic C (SOC) storage with NT compared with conventional tillage (CT) from published reports representing 111 comparisons from 39 locations in 19 states and provinces in the USA and Canada. Potential SOC storage with NT compared with CT was greatest (ca.500 kg/ha/yr) in sub-humid regions of North America with mean annual precipitation-to-potential evapotranspiration ratios of 1.1-1.4 mm/mm. Much lower potential in SOC storage with NT compared with CT was observed in more extreme environments, including the dry Great Plains region and the cold, humid eastern provinces of Canada. However, more data are needed to validate and strengthen the confidence of these relationships. Soil order and soil textural class had little effect on potential SOC storage with NT. Interaction of tillage regime with other management variables on potential SOC storage occurred with cropping intensity, but not with level of fertilization. Potential SOC storage with NT compared with CT increased when cropping intensity increased, regardless of climatic conditions.