Author
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HILL, PETER - PURDUE UNIVERSITY |
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Stott, Diane |
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Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/17/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Conservation tillage systems are defined as those leaving at least 30% residue cover on the soil surface after planting. Use of combination chisel plows in corn residue is generally considered to be a conservation tillage system. Changes in the equipment operation and setup, however, can substantially affect the amount of residue that is incorporated into the soil. Our objective was to evaluate operational effects of a combination chisel plow equipped with coulter gangs on corn residue cover. Fall chisel plowing left higher levels of residue cover than did spring chiseling. The difference was negated, however, when over- wintering losses following fall chiseling were accounted for. Only three of eight treatments during spring chiseling left residue cover greater than 30%. 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 didn't impact the surface residue cover. Depth of chiseling was not significant within the range used. Slowing the operation speed from 4 to 2 mi h-1 had more effect than slowing from 6 to 4 mi h-1. The highest residue cover and burial coefficients were associated with the slowest chiseling speed. Changing chisel points had a greater effect on surface cover than changing speed. Often using a combination chisel plow for primatry tillage won't leave sufficient residue after planting operations to meet control objectives. This will impact how farmers achieve their erosion control objectives. Adequate surface cover can still be achieved. Technical Abstract: 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 equipment operation and setup can substantially affect the amount of residue that is incorporated into the soil. Our objective 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 over-wintering losses following fall chiseling were accounted for. Three of eight treatments during spring chiseling left residue cover greater than 30%. 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. While the coulter gangs effectively sized residue, they had no significant impact on surface residue cover. Slowing the speed of operation from 6.4 km h-1 to 3.2 km h-1 had more effect than slowing from 9.6 m h-1 to 6.4 km h- 1. The highest residue cover and burial coefficients were associated with the slowest speed. 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 water erosion; however, residue cover levels following secondary tillage and planting operations will likely fall below 30%. |
