坡度因子(S)是土壤流失方程(USLE)中最重要的因子之一。本研究收集、整理、分析了西南土石山区典型区域的径流小区资料,修正了西南土石山区土壤流失方程的S因子算法。新算法将坡度分为≤5°、5°~10°、10°~25°和>25°四个范围,建立了分段的S因子计算公式。结果表明:增加10°~25°和>25°两级,较好地解决了西南土石山区陡坡地S因子的计算问题,计算精度较USLE、RUSLE、刘宝元算法、杨子生算法有明显提高。该算法可应用于西南土石山区土壤流失预报工作,提高了土壤侵蚀评价精度。 更多还原
 

Slope factor is one of the most important factors in Universal Soil Loss Equation ( USLE) ． The paper collected，sorted out and analyzed the data of runoff plots of typical rocky mountain area of southwest China and revised the algorithm of slope factor of Universal Soil Loss Equation． The new algorithm divided slopes into four types of ≤5°，5° ～ 10°，10° ～ 25° and ＞ 25° and established an equation for each type． The outcomes show that increasing two types of 5° ～ 10° and ＞ 25° can nicely solve the calculation of slope factor of steep slopes in the rocky mountain area of southwest China． Comparing the algorithms of USLE，RUSLE，LIU’s and YANG’s regressive model，the calculation accuracy has been significantly improved． The new algorithm can be applied to the soil erosion forecasting of the rocky mountain area of southwest
China and has effectively improved the accuracy of soil erosion evaluation．