Submitted to: ASAE Annual International Meeting
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 5, 1998
Publication Date: N/A
Interpretive Summary: The soils of the Lower Mississippi Delta are about equally divided between clay and other soils with lighter textures. Clay is very fertile, but its high sensitivity to drought stress reduces crop yields during most years to levels far below that produced on soils with properties that allow good water movement into the soil and storage of that water. One approach to enhancing the movement of water into clay soil has been the use of deep tillage tools when the clay was relatively dry. Tillage under this condition acts to disrupt the clay structure by moving the structural blocks around so that more space is created between them for water to flow through. This approach has resulted in significant increases in crop yield compared to yield from conventional disk harrow tillage on clay soils. This study extended the investigation of crop response to clay soil tillage by comparing conventional tillage practices to soil profile modification tillage which breaks the structural blocks of clay down into small pieces and mixes the different soil layers together. Results showed that cotton yield improved by as much as 500 kg/ha for profile modification tillage to depths of 76 cm. Yield improvement increased with depth of profile modification tillage. Residual effects of profile modification tillage persisted for 3 years for the 76 cm depth of profile modification. While profile modification produced a positive response in cotton production, time requirements were excessive for performing this practice.
Technical Abstract: A field study was established in the fall of 1993 on Tunica clay soil to evaluate the response of cotton to profile modification tillage relative to more conventional types of tillage for clay soil. A wide-bed controlled-traffic production system was used. Ten treatments were replicated 4 times using plots 15 m wide x 305 m long. Annual tillage treatments included bedding, disking, chiseling, subsoiling, and profile modification to depths of 25, 50, and 76 cm. Treatments to evaluate the residual effects of tillage were also included for the 25, 50 and 76 cm depths of profile modification. Results indicated that soil profile modification generally increased plant height, vegetative dry mass and seed cotton yield compared to conventional tillage practices. In the modified profile treatments, crop response increased as depth of modification increased. The residual effect of soil profile modification at the 76 cm depth was as effective in increasing seed cotton yield as annual modification after three years. Soil profile modification produced a positive response in cotton production but time requirements were excessive.