Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: 4/7/2000
Publication Date: N/A
Technical Abstract: In the southeastern US, disruption of deep soil pans is needed either with or without surface tillage. Deep disruption can be accomplished with minimal disturbance of the soil surface, thus maintaining organic cover and erosion control. Energy can be saved if crops are planted without surface tillage. If soils are surface tilled, it is generally believed that deep disruption eliminates any compaction that might be caused by surface tillage. We hypothesized that it was not. Double-cropped soybean and wheat were drilled in 7.5-inch (19-cm) row widths using all combinations of surface tillage (disked or none) and deep tillage (paratilled or none) with one extra set of paratilled treatments that were rotated with 30-in (76-cm) row width corn using an in-row, straight shank subsoiler. Soil strengths were measured at two places in each plot to assess differences within and among treatments. Soil strengths were higher for soil types with shallower rB horizons. Soil strengths were higher for subsoiled treatments than paratilled treatments, partially as a result of drier soil. When compared to non-disked treatments, soil strengths were equal or higher for disked treatments, even if treatments were deep tilled after surface tillage. In fact, at the position of maximum disruption by deep tillage, soil strengths were higher for disked treatments than non-disked treatments. A reduction in the beneficial loosening effect of the final deep tillage can be affected by earlier surface tillage.