Operational effects of a combination chisel plow on corn residue cover

Peter Robin Hill, Purdue University

Abstract

Combination chisel plows are used extensively in crop production areas in the United States as part of conventional, reduced, and mulch-tillage systems. Use of combination chisel plows in corn residue can reduce surface residue cover to levels that afford little protection from soil erosion processes. Changes in the operation and setup of the equipment, however, can significantly affect the amount of residue that is incorporated into the soil. The objective of this project was to evaluate operational effects of a combination chisel plow equipped with coulter gangs on corn residue cover. Variables included timing of chisel plowing, chisel point selection, speed and depth of chiseling, and coulter gang engagement. Fall chisel plowing left higher levels of residue cover than did spring chiseling. The difference was negated, however, when overwintering losses following fall chiseling were accounted for. Only three of eight treatments during spring chiseling left residue cover greater than 30%. Regardless of timing of chisel plowing, ranking of burial coefficients for the chisel points studied were: 406-mm low crown sweep = DMI Tiger-C specialty point $>$ 51-mm chisel shovel $>$ 102-mm twisted shovel. The 406-mm sweep and the DMI Tiger-C points had burial coefficients above 50% for fall chiseling and 40% for spring chiseling. While the coulter gangs effectively sized residue, they had no significant impact on surface residue cover. Depth of chiseling was not significant within the experimental range used. Slowing the speed of operation from 6.4 km h$\sp{-1}$ to 3.2 km h$\sp{-1}$ had more effect than slowing from 9.6 m h$\sp{-1}$ to 6.4 km h$\sp{-1}.$ The highest residue cover and burial coefficients were associated with the slowest chiseling speed of 3.2 km$\sp{-1}.$ Overall, changing chisel points had a greater effect on surface residue cover than changing speed. Primary tillage of corn residue using a combination chisel plow can provide adequate soil surface protection from soil erosion processes; however, residue cover levels following secondary tillage and planting operations will likely fall below 30%.

Degree

Ph.D.

Advisors

Stott, Purdue University.

Subject Area

Agronomy|Agricultural engineering|Soil sciences

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