Author
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Reicosky, Donald |
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Submitted to: World Congress on Conservation Agriculture
Publication Type: Proceedings Publication Acceptance Date: 10/5/2001 Publication Date: 10/5/2001 Citation: REICOSKY, D.C. TILLAGE-INDUCED CO2 EMISSIONS AND CARBON SEQUESTRATION: EFFECT OF SECONDARY TILLAGE AND COMPACTION. GARCIA-TORRES, L. ET AL. EDITORS. XUL, CORDOBA, SPAIN. CONSERVATION AGRICULTURE, A WORLDWIDE CHALLENGE. 2001. P. 265-274. Interpretive Summary: The increase in atmospheric CO2 raises concerns about potential global warming. Cumulative effect of tillage and cropping rotations caused a 30-50% decrease in soil C resulting in undesirable changes in soil physical, chemical and biological properties. Recent tillage method studies indicate major C loss immediately after tillage. This work demonstrated that secondary tillage methods decreased CO2 loss immediately following the moldboard plow. Both disk harrow and field cultivator reduced the CO2 flux by 40 to 50% immediately following the moldboard plow. Major soil reconsolidation with one pass of a packer caused an abrupt decrease in CO2 flux after primary tillage by moldboard plow, chisel plow, subsoiler and paraplow tillage implements. Further small decreases in CO2 fluxes were noted with four packer passes. Abrupt decreases in gas exchange were related to increases in soil bulk density following compaction. Results demonstrate importance of soil physical properties before and after tillage that control soil C loss. Results are significant to farmers and policy makers in that intensive tillage causes substantial short-term CO2 loss. This information will assist scientists and engineers to develop improved secondary tillage methods to minimize gaseous loss and improve soil C management. Farmers can develop and utilize new management techniques for enhancing soil C by increasing quantity and quality of crop residues and by changing the intensity of tillage. Farmers will benefit from information to maintain crop production with minimal impact on air quality and environment. Technical Abstract: Long-term data shows the effect of intensive tillage on soil carbon loss and suggests the need for alternative management strategies. Conservation agriculture with improved tillage methods can aid in carbon sequestration. This work demonstrated that secondary tillage methods decreased the carbon dioxide loss immediately following the moldboard plow. Both the disk harrow and the field cultivator reduced the carbon dioxide flux immediately following the moldboard plow operation by 40 to 50%. Major soil reconsolidation with one pass of a road packer caused an abrupt decrease in the carbon dioxide flux after primary tillage by moldboard plow, chisel plow, subsoiler and paraplow. Further small decreases in carbon dioxide fluxes were noted with four passes of the packer. The abrupt decreases in gas exchange were related to increases in soil bulk density following the compaction. These results demonstrate the importance of soil physical properties before and after tillage controlling gas fluxes and soil carbon loss. |
