Soil Disturbance and the Potential for Erosion After Mechanical Site Preparation

Abstract

Abstract Physical soil properties created by three mechanical site preparation treatments (ripper ploughing, disc trenching, and blading) and a control were evaluated to determine the success of these different mechanical site preparation treatments in creating plantable microsites and to estimate the potential for soil erosion created by each treatment. Three sites with fine textured soils and high water contents near Whitecourt, Alberta, Canada), were selected for study. The topography at all sites was similar and characterized by slopes 3.7 to 20% in steepness and approximately 190 to 270 m in length extending from the height of land to stream bottoms. The number of planting sites and the soil characteristics suggest ripper ploughing as the best site preparation treatment in this study, with the hinge microsite as the preferred planting spot. All three treatments significantly improved the physical conditions of the soil compared to the control, although the differences among treatments were small. Soil erosion was observed on areas where blading and ripper ploughing exposed mineral soil. Gullies, which exposed the roots of seedlings, were created by water erosion in the blading treatment area. Sediment deposition in trenches was observed on ripper ploughed areas, and at times, seedlings within this treatment area were partially buried as a result of this soil movement.