|Yoder, D - UNIVERSITY OF TENNESSEE|
|Zhu, Jingcai - ARS|
|Douglas, Joel - USDA-NRCS|
Submitted to: International Symposium on Soil Erosion and Dryland Farming
Publication Type: Proceedings
Publication Acceptance Date: November 1, 2000
Publication Date: N/A
Interpretive Summary: Conservation planning requires accurate estimation of current and future soil erosion rates. When tilled hillslopes are divided by buffer strips or grass hedges, soil movement by tillage and by water erosion/deposition processes can change slope steepness over time. Generally, soil is lost from the upslope edge of tilled areas and deposited near their downslope edges. Current versions of the erosion models RUSLE and WEPP do not automatically account for such changes. In this paper we use the sediment deposition predictions of these models and modify, outside of the programs, an approximately 250-ft long hillslope containing grass strips. We found that predicted slope changes were similar to those observed in a 7-yr old field study. Predicted erosion rates were reduced by 40 to 50% by slope shape changes observed. These results demonstrate the importance of considering landscape modification for long-term conservation planning of sloping fields containing permanent grass strips. They also demonstrate that a reasonable job of accounting for such effects can be done using existing models when simple assumptions about the location and shape of sediment deposits capture the main effects of hillslope topographic changes. The approach demonstrated will be of use to conservationists planning erosion control systems for strip cropped fields in the 21st century.