Is Deep Zone Tillage Agronomically Viable in Minnesota?

Abstract

Deep zone tillage is a strategy used to alleviate compaction problems, including plow pans, and to improve internal drainage. Midwestern soils do not typically form a defined plow pan under normal production practices. Despite lack of scientific evidence for yield benefits associated with deep tillage, it is still used in Minnesota as a low cost alternative to tile drainage. To evaluate the soil and economic impact of deep zone tillage on crop yield when a restrictive layer is lacking, a 20-acre field was deep zone tilled to a 20-inch depth, every other 12 rows at 30-inch spacing. After zone tilling, the entire field was ridge tilled. Ridge tillage confines wheel traffic to the same rows, reducing the percent of the field trafficked. All crop and soil measurements were collected in the depressional and upland areas of the field to distinguish if zone till is of benefit in different landscape areas. Crop yields were measured for two seasons following zone tilling a ridge-tilled field. Zone till failed to increase corn and soybean yields. A restrictive layer was not observed in this field and as a result, potential economic losses occurred due to deep zone tillage.