Author
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Reicosky, Donald |
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Archer, David |
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Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/10/2006 Publication Date: 5/1/2007 Citation: Reicosky, D.C., Archer, D.W. 2007. Moldboard plow tillage depth and short-term carbon dioxide release. Soil & Tillage Research. 94:109-121. Interpretive Summary: Soil carbon (C) losses and soil translocation from intensive tillage operations have been identified as causes of soil degradation and soil erosion. Elevated atmospheric carbon dioxide (CO2), potential global warming concerns and prospective use of soil as a sink for carbon attracted interest from farmers and land managers. Recent studies involving tillage methods indicate major gaseous loss of C immediately after tillage. Information is needed on the mechanism and magnitude of greenhouse gas generation and emission from agricultural soils with specific emphasis on tillage mechanisms. This work describes variation in CO2 losses as a result of moldboard plow tillage depth. The CO2 release immediately following tillage increased with increasing plow depth, and in every case was substantially higher than that from the no-tillage treatment. The smaller CO2 loss with shallow tillage was significant and suggests progress is being made in understanding the effect of tillage intensity on soil C management. This information will assist scientists, engineers and policy makers in developing improved tillage methods to minimize the gaseous loss and to improve soil C management. Farmers can develop and utilize new management techniques for enhancing soil C by increasing the quantity and quality of crop residues and by changing the type and intensity of tillage. Any effort to decrease tillage depth and maximize crop residue return to the soil surface should result in lower fuel consumption and increased soil C sequestration for enhanced environmental quality. Incorporating C storage in conservation planning demonstrates concern for our global resources and presents a positive role for soil C policies and our future quality of life. Technical Abstract: Agricultural ecosystems can play a significant role in the production and consumption of greenhouse gases, specifically, carbon dioxide (CO2). Intensification of agricultural production is an important factor influencing greenhouse gas emission, particularly the relationship between intensive tillage and soil carbon (C) loss. Information is needed on the mechanism and magnitude of greenhouse gas generation and emission from agricultural soils with specific emphasis on tillage mechanisms. The specific objective of this work was to evaluate the short-term effects of moldboard plowing depth on CO2 loss from a Barnes loam (Udic Haploboroll, fine loamy, mixed) in west central Minnesota, U.S.A. Experimental treatments were weed-free replicated plots, moldboard plowed to depths of 102, 152, 203, and 280 mm deep using two passes of a four-bottom conventional moldboard plow following harvest of a spring wheat (Triticum aevestium, L.) crop that was compared with an undisturbed area (no-tillage). The CO2 flux was measured immediately after the tillage with a large portable chamber commonly used to measure crop canopy gas exchange and continued intermittently for several hours after the initial tillage and at 24 and 48 h and periodically to 500 h after tillage. The treatment flux data at each tillage depth was fitted to the same function for temporal trends and statistical analysis. The CO2 release immediately following tillage increased with increasing plow depth, and in every case was substantially higher than that from the no-tillage treatment. The smaller CO2 loss with shallow tillage was significant and suggests progress is being made in understanding the effect of tillage intensity on soil C management. Any effort to decrease tillage depth and maximize crop residue return to the soil surface should result in lower fuel consumption and increased soil C sequestration for enhanced environmental quality. |
