Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/1995
Publication Date: N/A
Interpretive Summary: Soil compaction from heavy farm machinery is often considered to be a serious crop production factor in Midwest soils. Farmers often use deep tillage (subsoiling) to overcome this problem; but the benefits, if any, are difficult to document in production-scale farming. A field experiment was conducted in Morris, MN, on a clay loam soil to determine the effect of fsubsoiling on soil properties and corn yield. Plots were subsoiled 16 inches deep in the fall of 1988 prior to being tilled with various degrees by fall and spring tillage treatments, including no-till. Various soil and corn growth measurements were taken over the next three growing seasons. Bulk density, one measure of compaction, was significantly decreased the year following subsoiling, but by the second and third year, there were no measurable differences. Corn growth and yield were not significantly affected by deep tillage in any year. Thus, farm producers must carefully evaluate the perceived need to subsoil, and balance this against the probability of realizing an economic crop yield increase; subsoiling is an expensive operation, and research data does not support subsoiling on a routine basis.
Technical Abstract: Many producers use subsoilers periodically to alleviate expected compaction due to traffic from tillage, planting, and harvesting equipment. In the fall of 1988, a study was initiated near Morris, MN, to study the effects of a one-time subsoiling and its interaction with various primary tillage systems on subsequent soil compaction, soil moisture, penetrometer resistance, and corn (Zea Mays L.) growth and yield. The experiment was established on a Hamerly clay loam (Aeric Calciaquoll) a moderately well- drained calcareous soil formed on loam and clay, and Aastad clay loam (Pachic Udic Haploboroll) a moderately well drained soil developed in loamy till, 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 equipment and on which serious compaction problems had not been observed. Results show that subsoiling had no effect ton plant growth or 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 1990-91 these effects were no longer significant. Volumetric soil moisture content generally increased in relation to soil bulk density increases. Results from this study indicate that subsoiling soils that do not have serious compaction problems does not result in better yields or better soil moisture availability.