Author
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Reeves, Donald |
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Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 8/5/2004 Publication Date: 9/8/2004 Citation: Reeves, D.W. 2004. Adopting lessons from Brazil for conservation tillage in the southeastern USA. Proceedings 2004 Western States Conservation Tillage Conference-Linking Economics, with Air, Water and Soil Wuality, University of California, West Side Research and Extension Center, Five Points, California, September 8-9, 2004. p. 31-45. Interpretive Summary: Many farms in the southeastern USA have soils that are degraded from long-term continuous cropping with conventional tillage, resulting in soil erosion and loss of organic matter. Although conservation systems can reverse this degradation, the USA has much to learn from its neighbors in South America about development and adoption of sustainable conservation systems. Brazilian research has shown the benefit of intensive rotations, high-residue cover crop production, and conservation tillage to improve soil productivity. USDA-ARS scientists at the J. Phil Campbell Sr. Natural Resource Conservation Center, Watkinsville, GA, and the Soil Dynamics Research Unit, Auburn, AL have adapted the Brazilian model to specific soil types; to manage soil compaction, improve soil quality, and reduce risks from short-term droughts. They found that the use of high-residue producing cereal and/or legume cover crops, combined with a form of deep tillage to reduce soil compaction while maintaining residues on the soil surface are keys to successful management of these soils. Refinements for the systems include adjusting planting dates of cover crops and cash crops to maximize residue production, modifying equipment to perform in heavy residue, and more recently, the use of Real-Time Kinematic Global Positioning System (RTK-GPS) guidance systems for equipment. This information has been used by growers, consultants, state extension services, and USDA-NRCS to promote adoption of conservation tillage in the southeastern USA. Conversion of over 1.3 million acres of cotton in the Southeast since 1998 saves 10.6 million tons of soil annually, worth $198 million in on-farm and off-site impacts. Technical Abstract: Many soils of the southeastern USA are degraded from continuous cropping of cotton (Gossypium hirsutum L.) and subsequent soil erosion and loss of organic matter. Brazilian research has shown the benefit of intensive rotations, high-residue cover crop production, and conservation tillage to improve soil productivity. In the southeastern USA, we have adapted the Brazilian model to specific soil types; to manage soil compaction, improve soil quality, and reduce risks from short-term droughts. For all soils, the use of high-residue producing cereal and/or legume cover crops is the crucial management component. For silty-clay soils, a cereal cover crop is used with non-inversion under-the-row tillage in fall. For coarser-textured coastal plain soils with root-restricting compacted layers, the non-inversion tillage is accomplished in spring, as these soils reconsolidate with winter rainfall. Coastal plain soils allow greater diversity in choice of cover crops. Refinements for the systems include adjusting planting dates of cover crops and cash crops to maximize residue production, modifying equipment to perform in heavy residue, and more recently, the use of Real-Time Kinematic Global Positioning System (RTK-GPS) guidance systems for equipment. These practices have played a key role in the dramatic increase of conservation tillage adoption in the southeastern USA. |
