WEPP模型在东北黑土区的适用性评价--以坡度和水保措施为例

Assessment of WEPP Model Applicability in Black Soil Zone of Northeast China——A Case Study of Slope Gradient and Soil and Water Conservation Measures

基于黑龙江省宾县试验站2008年气象观测数据和野外径流小区监测资料,利用WEPP模型估算东北黑土区次降雨径流量和土壤流失量,并通过与实测资料对比,评价WEPP模型的适用性。结果表明,在3°,5°,8°这3个坡度条件下,WEPP模型对次降雨径流量模拟的Nash—Sutcliffe有效性系数ME分别为0.47,0.03和-5.9,对次降雨土壤侵蚀量模拟的Nash—Sutcliffe有效性系数ME分别为0.58,0.72和0.60,说明WEPP模型对次降雨坡面径流量的模拟效果较差,而对次降雨坡面土壤侵蚀量模拟效果较好。WEPP模型对次降雨的径流量和土壤流失量的模拟显示,WEPP模型对坡度变化反应敏感。WEPP模型对大豆、稗草、苜蓿和苗期榆树次降雨径流量模拟有效性系数ME分别为0.81,0.71和0.83,0.94,对次降雨土壤流失量的模拟有效性系数ME分别为0.81,0.71和0.83,0.94,表明WEPP对大豆地和苜蓿地的模拟效果好于稗草和苗期榆树,且其好于不同坡度条件下裸地的模拟结果。WEPP模型可以模拟不同水保措施条件下的次降雨径流量和土壤侵蚀量,也可以模拟不同坡度条件下裸地的次降雨土壤侵蚀量,但是不适合模拟不同坡度条件下裸地的次降雨径流量。

Based on data observed from the automatic meteorological station near runoff plots and measured soil loss data from field runoff plots at Binxian Experimental Station in 2008, runoff and soil loss from the plots in black soil zone, Northeast of China were simulated. The simulation results were compared with measured values and the applicability of WEPP model was assessed. Results showed that Nash--Sutcliffe model effieiencies of event runoff simulation on different slopes by WEPP were 0.47, 0.03, and -5.9, respectively. Nash--Sutcliffe model efficiencies of event soil loss simulation were 0.58, 0.72, and 0.60, respectively. It indicated that event simulation result of soil loss was better than event simulation result of runoff. WEPP model was sensitive to the change of slope. Nash--Sutcliffe model efficiencies of event runoff simulation to soybean, Dallis grass, alfalfa, and elm were 0.81, 0.71, 0.83, and 0.94, whereas Nash-Sutcliffe model efficiencies of event soil loss simulation were 0.81, 0.71, 0.83 and 0.94, respectively. This show that simulation results of alfalfa and soybean were better, compared with simulation results of grass and elm and simulation results of bare land on different slopes. From the above results, WEPP can be used to simulate event runoff and soil loss under different soil and water conservation measures and event soil loss at different slope gradients on bare land, but it is not suitable to simulate event runoff at different slope gradients on bare land.