TECHNICAL NOTE Effectiveness of a Winged Subsoiler in Ameliorating a Compacted Clayey Forest Soil

:‘)ii$ Machine piling of slash and brush after harvest is commonly practiced when establishing new conifer plantations. However, it can result in increased soil bulk density, decreased soil macroporosity, and increased soil strength, thus reducing conifer root development and above-ground growth (Froehlich 1979, Sands and Bowen 1978). Because natural recovery of soil from compaction is slow, ways have been sought to restore compacted soils through tillage. Brush rakes, rock rippers, and disk harrows have not been successful in creating proper soil conditions for optimum tree root growth, because they push soil aside and turn it over, often while fracturing less than 40% of the compacted layers. In the early 1980s the effectiveness of four types of tillage implements were tested on compacted soils by Andrus and Froehlich (1983). They found that brush rakes, rock rippers, and disk harrows were seldom effective; but that the winged subsoiler showed promise, sometimes fracturing 80% of the compacted soil layers (Froehlich and Miles 1984). More recently, when the winged subsoiler was compared to rock rippers on compacted soils, it provided superior profile shatter of 137% versus 26% based on 12-in. depths (Carr 1989). The objectives of this study were to determine if brushpiling machinery caused significant soil compaction and to determine if soils compacted during brush piling could be tilled to achieve a bulk density similar to that of undisturbed soil. Further, these soil conditions were compared with these soils in a nearby unit that had been tractor-logged 22 years previously and that had not been tilled.