Effect of subsoiling and subsequent tillage on soil bulk density, soil moisture, and corn yield

Many producers use subsoilers periodically to alleviate suspected compaction caused by traffic from tillage, planting, and harvesting equipment, In the fall of 1988 a study was initiated in the upper Midwest region of the USA near Morris, Minnesota to study the effects of a one-time subsoiling and its interaction with four subsequent primary tillage systems (fall moldboard plowing, fall chisel plowing, spring disking, and no-tilling) on soil compaction, soil moisture, penetrometer resistance, and corn (Zea mays L,) growth and grain yield, The experiment was established on a Hamerly clay loam (Aeric Calciaquoll)-Aastad clay loam (Pzchic Udic Haploboroll) complex, Subsoiling was performed in the fall of 1988 and the study was cropped to continuous corn from 1989 to 1991 on a site that had been farmed many years by normal 6-row, 76-cm row width equipment, Results show that subsoiling had very little effect on plant growth and no effect on grain yield over three cropping seasons following the subsoiling operation, Subsoiling had significant effects on soil bulk density and volumetric soil moisture content in 1989, but by 1990-1991 these effects were not significant. Volumetric soil moisture content generally increased in relation to soil bulk density increases. Tillage impacted surface residue accumulation, but did not affect soil bulk density, volumetric soil moisture, or grain yield, Results from this study indicate that subsoiling soils does not necessarily result in better yields or better soil moisture availability, particularly if compaction problem are not evident.