Soil movement by tillage as affected by slope

The purpose of this study is to determine if soil erosion on ridge tops may be in part caused by tillage moving soil downslope and to quantify the relationship between slope gradient and soil movement. The research took place at the University of Minnesota Southwestern Experiment Station on hillside plots with a 1-8% grade slope. Plots were tilled up and down or across the slope by moldboard plough and disc. While it is widely accepted that tillage indirectly contributes to erosion by making the soil more vulnerable to wind and water erosion, they find that the act of tillage itself directly erodes soil on slopes. They found a direct relationship between soil movement and slope; on an 8% grade, the movement downhill (perpendicular to plow movement) was double uphill movement.