Unlike water erosion, tillage erosion is not strongly affected by slope length. Therefore, in hilly regions that have many changes in slope, tillage erosion can be the dominant erosive force, explains Thomas Schumacher, retired SDSU Plant Science Professor.
"Tillage erosion is the downslope movement of soil by tillage. During tillage, soil is lifted and gravity moves soil downslope. Soil movement by tillage increases with slope steepness. However, net soil transport by tillage is determined by the change in slope. Soil movement by tillage very slowly levels the land surface. Soil is removed from areas where slope is increasing (convex) and deposited in areas where slope is decreasing (concave)," said Schumacher.
He adds that this applies in the eastern Dakotas, western Minnesota, and throughout the Prairie Pothole Region.
Conditions that Schumacher says influence tillage erosion include: intensive tillage; the tillage operation - implement design; depth, speed, and direction of tillage; topography - curvature, change in slope, steepness; and soil properties - bulk density and soil texture.
"Any implement that lifts the soil will cause tillage erosion," he said. "Some secondary operations are as erosive as primary tillage operations."
Soil changes resulting from tillage erosion
Tillage erosion degrades soil quality in upper slope positions.
"The additive effect of years of combined tillage, water and wind erosion is shallow topsoil in the upper slope (sometimes with exposed subsoil) and deep topsoil accumulation in depressions," Schumacher said.
He adds that erosion also changes soil organic matter content, soil texture, water holding capacity, nutrient availability, aeration, pH and other soil properties that affect productivity.
When it comes to productivity changes resulting from tillage erosion, Schumacher says tillage erosion depletes crop yield in areas of soil loss.
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