Relative Effectiveness of Tillage and Natural Forces in Alleviating Wheel‐Induced Soil Compaction

Abstract

AbstractWheel‐induced soil compaction can have detrimental consequences in reduced tillage systems if off‐season weathering forces are not very effective in ameliorating a compacted soil. Field studies were conducted on a Nicollet silty clay loam (Aquic Hapludoll) in Minnesota on plots with a history of controlled wheel traffic. After 5 years of autumn tillage, the plots were split, with one‐half of each plot moldboard plowed or reduced tilled (chisel plow or tandem disk) and the other one‐half remaining untilled over the winter period. Bulk density, penetrometer resistance, soil water content, aggregate size, and clod density were measured to assess the relative effect of natural forces and tillage on amelioration of wheel track‐compacted soil. Moldboard plowing in the autumn effectively ameliorated compaction of the bulk tilled layer. Reduced forms of tillage such as chisel plow or tandem disk were only slightly more effective than natural weathering forces which reduced penetrometer resistance by 20 to 50%, but had little effect on bulk density. The structure of individual soil aggregates and clods was not changed much by either tillage or natural weathering. Thus, a no‐till system may result in higher bulk density, aggregate density, and penetrometer resistance because of incomplete amelioration of compacted soil by natural forces during the winter season. Potential consequences include seedbed preparation problems, uneven germination, lower hydraulic conductivity, and undesirable early root growth environment.