Author
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Reicosky, Donald |
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Submitted to: Proceedings of Argentine National No Till Congress
Publication Type: Proceedings Publication Acceptance Date: 8/20/1999 Publication Date: N/A Citation: N/A Interpretive Summary: The increase in the carbon dioxide in the atmosphere has attracted interest in Argentina due to the concerns about potential global warming and the prospects of using soil as a sink for carbon released by human activity. The cumulative effect of tillage and many cropping rotations has been a 30- 50% decrease in soil carbon that causes an undesirable change in soil physical, chemical and biological properties. This review covers recent studies involving tillage methods that indicate major gaseous loss of carbon immediately after tillage. Differences in the CO2 losses as a result of tillage methods were related to soil fracturing that facilitated movement of carbon dioxide out of and oxygen into the soil. This review evaluates (1) the longer-term impact of various residue management options (silage removal) on CO2 loss, (2) seasonal effects of strip tillage, 3) independently verifies tillage-induced CO2 loss without the portable chamber, and (4) demonstrates the long-term impacts of moldboard plowing related to environmental benefits of soil carbon storage. Progress is being made in developing conservation tillage tools that can further enhance soil carbon management. These results are significant to farmers and policy makers in that tillage results in substantial short-term gaseous losses of CO2. This information will be of direct benefit to the farmers to enable them to maintain crop production with minimal impact on the environment. Farmers can develop and utilize new management techniques for enhancing soil carbon by increasing the quantity and quality of crop residues and by changing the type and intensity of tillage. This information will assist scientists and engineers to develop improved methods of tillage to minimize the gaseous loss and improved soil carbon management. Technical Abstract: Agriculture is the major industry for food and fiber production that can serve as both sources and sinks of greenhouse gases. Intensification of agricultural production is an important factor influencing greenhouse gas emission. This review covers the role of agriculture as a means of sequestering soil carbon and minimizing possible environmental consequences sof intensive agriculture. Removal of corn silage for 30 years as compared to returning the residue and removing only the grain resulted in no difference in the soil C content after 30 years of continuous corn and moldboard plowing. The short-term CO2 flux in the strip tillage study was generally the largest for the moldboard plow and least in the not tilled treatment. Other forms of strip tillage were intermediate and only a relatively small amount of CO2 was detected immediately after strip tillage. The tillage-induced plume of CO2 from a plowed strip perpendicular rto the prevailing wind was demonstrated in the absence of the chamber. As we learn more about soil C storage and its central role in direct environmental benefits, we must understand the secondary environmental benefits and what they mean to production agriculture. Increasing soil C storage can increase infiltration, increase fertility, decrease wind and water erosion, minimize compaction, enhance water quality, decrease C emissions, impede pesticide movement and enhance environmental quality. Incorporating C storage in conservation planning demonstrates concern for our global resources and our future quality of life. |
