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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #95519


item Lindstrom, Michael

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soil movement from tillage implements has been identified as a cause of soil erosion on sloping lands. Soil is lost from convex slope positions and deposited in concave slope positions. Soil movement from convex slope positions can exceed soil erosion amounts that would be viewed as unacceptable by wind or water erosion. The magnitude of soil loss or gain along the landscape is dependent on the degree of slope curvature rather than slope steepness. A tillage erosion prediction simulation (TEPS) model was developed to simulate soil movement from individual tillage operations or a sequence of tillage operations based on published soil movement data. Soil loss (erosion) or gain (deposition) is calculated along a field transect and identifies areas where soil movement by tillage produces an unacceptably high level of soil erosion. Results from the TEPS model identify field landscape positions with observable soil erosion problems that cannot be explained by wind or water erosion models. The TEPS model can be used by conservation planners and farm managers to determine the severity of tillage erosion on their agricultural fields. The model can also be used in combination with wind and water erosion models to identify problem soil erosion areas and be used as a guide in conservation planning.

Technical Abstract: Soil movement by tillage is a function of slope gradient and when tillage is performed up- and downslope in opposing directions, a net downslope movement of soil is the result. This movement produces annual soil erosion rates from specific landscape positions that can exceed soil loss tolerance levels. The objectives of this study were to develop a simulation model to odescribe soil redistribution along a hillslope transect which can be used to explain observed erosion and deposition patterns in cultivated fields that cannot be accounted for by wind or water erosion models. The distance soil will move when tilled is statistically correlated with slope gradient and a diffusion-type constant (k) has been developed which effectively described net downslope soil movement rates at any point on the landscape. Using the diffusion process concept, soil redistribution was calculated over a 50-year period on a measured topographic transect in west central Minnesota. Results from these simulations showed that 14.7% of the area in the transect would experience a loss or gain in soil that exceeded 10 t ha**-1 yr**-1 with a k value of 234 kg m**-1. The loss or gain in soil that exceeded 10 t ha**-1 yr**-1 increased to 26% of the area with a k value of 330 kg m**-1. The addition of secondary tillage (two disk operations) increased the area of excessive soil redistribution to 50%. Increasing the lengths of analyzed soil segments from 1 to 10 m resulted in some loss of precision, but in general similar rates of soil redistribution were observed. The TEPS model has the capability to identify areas of excessive soil loss (erosion) or gain (deposition) from tillage system management and will be a useful tool in the development of sustainable crop production systems.