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United States Department of Agriculture

Agricultural Research Service

Title: Slope Length Effects on Soil Loss for Steep Slopes

item Nearing, Mark

Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 23, 1999
Publication Date: N/A

Technical Abstract: An empirical soil erosion model is still playing an important role on soil conservation planning and environment evaluations. Slope length factor is one of the main and the most variable factor in an empirical model. Many farmlands are on very steep slopes on loess plateau in China. The purpose of this study is to verify which exponent (USLE or RUSLE) is better adapted to the steep land on loess plateau. Soil loss data from natural runoff plots at three locations on the loess plateau in China were used to assess the effect of slope length on soil loss for very steep slope. The slope length for Zizhou location was 20,40,60 meters with slope steepness of 40.4%, the plot length for Suide station was 10, 40, 60 meters with 40, 42.8, 40% slopes respectively; the length of slope for Ansai was 10, 20, 30, 40 with 57.7% slope steepness. The width for all of the three locations was 5 meters and the land management for Zizhou and Suide were cropland with low density of crop cover but fallow for Ansai location. The soils were loam or silt loams. The results indicated that for these plots, the exponent, m, for the relationship between soil loss and the slope length, was 0.49,0.48, 0.40 respectively according to the equation L = (l/22.1) m, where l is the slope length and L is the slope length factor normalized to 22.13 m. This relationship was assessed in terms of the limited existing experimental data for rainfall erosion on steep slopes and would indicate that the USLE exponent, m=05 is adapted better for steep slope on loess plateau than the RUSLE exponent.

Last Modified: 7/30/2014
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