【作者】 刘远利；

【导师】 郑粉莉；

【作者基本信息】 西北农林科技大学 ， 地图学与地理信息系统， 2010， 硕士

【摘要】 土壤侵蚀预报模型是分析土壤侵蚀状况、制定水土保持方案和资源调查等工作的有效工具。水蚀预报模型WEPP(Water Erosion Prediction Project)建立之初就受到了各国学者的关注,关于WEPP在我国的应用,主要集中在长江中上游紫色土区和黄土高原地区;在东北黑土区的应用及其适用性评价研究还是一个空白。本文利用东北黑土区宾县宾州镇二龙山孙家沟小流域和海伦市西南前进小流域径流小区监测的次降雨产流和产沙数据,评价WEPP模型在东北黑土区的适用性。本论文主要的研究结论如下:1)采用敏感性分析方法分析了模型土壤和气候参数对WEPP模型模拟结果的影响。在次降雨模拟条件下,WEPP模型六个土壤参数中,土壤反照率、细沟土壤可蚀性、细沟间土壤可蚀性和临界剪切力四个参数对次降雨径流量的模拟结果没有影响,仅有初始饱和度和有效水力传导系数对径流量的模拟结果有影响。而初始饱和度、细沟间土壤可蚀性、细沟土壤可蚀性、临界剪切力和有效水力传导系数对WEPP模型次降雨土壤侵蚀量的模拟结果有重要影响。CLIGEN气候模型的四个参数中(降雨量、持续时间、最大雨强和峰值出现时间),径流量和土壤侵蚀量模拟值随着降雨量的增大而增大;WEPP模型对径流量模拟值随降雨持续时间的延长而变小;径流量和土壤侵蚀量的模拟值先随最大雨强的增大而增大,但峰值出现后,径流量和土壤侵蚀量的模拟值逐渐减小;峰值出现时间对径流量和土壤侵蚀量模拟值的影响较复杂。2)利用WEPP模型模拟了不同坡度条件下次降雨的径流量和土壤侵蚀量。WEPP模型对次降雨模拟值随坡度增加而增大,且增加的幅度变大,表明在当前条件下WEPP模型对径流量和侵蚀量模拟随坡度的变化较敏感。土壤侵蚀量的实测值和模拟值具有相同的变化规律,都随着坡度的增大而增大。与径流量的变化规律相比,WEPP模型对土壤侵蚀量模拟值随坡度变化比径流量模拟值随坡度变化更明显。在不同坡度(3°、5°和8°)条件下,模型对土壤侵蚀量模拟结果的模型有效性系数ME均大于0.5,表明模型对土壤侵蚀量模拟结果较好。通过对比不同坡度条件下模型模拟结果的有效性系数ME发现,模型对较小坡度的模拟效果较好,且土壤侵蚀量的模拟结果要明显好于径流量的模拟结果。3)利用WEPP模型模拟了不同植被条件下次降雨的径流量和土壤侵蚀量。WEPP模型模拟值的模型有效性系数ME均大于0.5,这说明模型模拟结果较好。在四种植物径流小区中,WEPP模型对于种植大豆和苜蓿草的径流小区模拟结果要好于稗草、苗期榆树的模拟结果。在四种植物的径流小区中,模型对径流量的模拟结果偏大,对土壤侵蚀量的模拟结果偏小。4)利用WEPP模型模拟了不同耕作措施条件下次降雨的径流量和土壤侵蚀量。WEPP模型对径流量的模拟结果基本可以接受,而模型对土壤侵蚀量的模拟值出现了一定偏差。WEPP模型对次降雨径流量模拟值的模型有效性系数ME中,少耕、传统耕作和裸地径流量模拟值的模型有效性系数ME分别为0.65、0.53和0.75,表明WEPP模型对少耕、传统耕作和裸地的径流量模拟结果可以接受;对免耕、少耕、传统耕作、裸地、黄坡垄地面处理,坡面侵蚀量模拟值的Nash-Sutcliffe有效性系数ME分别为-31.26、0.10、0.40、0.34和-1.02,表明模型对不同耕作措施土壤侵蚀量的模拟结果均不理想。WEPP模型对少耕、免耕和裸地径流量的模拟结果整体上好于其他耕作措施。5)利用黑龙江海伦试验站的气象资料和裸地径流小区的产流产沙资料,对比研究CLIGEN和BPCDG两种模型的模拟效果。结果表明,WEPP模型应用BPCDG模拟结果优于应用CLIGEN的模拟结果。更多还原

【Abstract】 Soil erison prediction model was an effective tool to assess soil erosion, design soil and water conservation scheme and resource survey. WEPP was concerned in soil and water conservation field since it was issued. WEPP application to China were mainly concentrated in the purple soil region of the middle and upper reaches of Yangzhe River basin and the Loess Plateau, but there is no WEPP application and assessment in the black soil region of Northeast China. This thesis used field observed data of runoff and soil loss from small watershed in Binxian and Hailun city, to predict runoff and soil loss under rain events at different slope gradients, different plants and different tillage measures, and then assessed the applicability of WEPP in northeast black soil region. The main research results were as follows:1)The sensitive analysis of WEPP soil parameters and climatic parematers showed that four soil parameters of albedo, interrill erodibility, rill erodibility, and critical shear in six parameters had no effect on predicted runoff result, but initial saturation and effective hydraulic conductivity affected the predicted runoff results. There was no effect of albedo on the hillslope soil loss; other five soil parameters affected simulated results. Among the four parameters related to climate under event prediction, hillslope runoff and soil loss increased with rainfall and decreased with duration time. They increased as maximum rainfall intensity, but after the peak occurrence, they gradually decreased. The impats of the peak occurrence on hilslope runoff and soil loss were relative complex.2)Hillslope runoff and soil loss at different slope degrees under single rain event were simulated by WEPP. The results showed that predicted hillslope runoff increased as slope degree increased, and its increasing scope tended to increase, which indicated WEPP simulated values were sensitive to the gradient change. Measured soil loss had the same trend. Compared with runoff change with slope degree, soil loss change was much more obvious. Model efficiency of soil loss prediction under different gradient slopes (3°, 5°and 8°) was larger than 0.5, which meaned that WEPP simulated results were accepted. WEPP simulated soil loss was better than simulated runoff. Compared model efficency at different gradient slopes, it was found that the simulated value for low slope was better than for steep slope. 3)Hillslope runoff and soil loss at different vegetation under single rain event were simulated by WEPP. The result showed that model efficency of runoff and soil loss was larger than 0.5, which meaned that the WEPP simulated results were accepted. Compared with grass and elm at seedling stage, the simulated results of soybean and alfalfa were better. The predicted runoff values were larger than measured values and the simulated values of soil loss were smaller than measured values.4)Hillslope runoff and soil loss at different tilliage measures under single rain event were simulated by WEPP. Predicted runoff by WEPP was accepted, but predicted soil loss was a little far from the measured values. Model efficiency of runoff prediction for mini- tillage, conventional tillage, and bare land were respectively 0.65, 0.53, and 0.75, which meaned that the prediction result was accepted. Model efficiency of soil loss prediction for non-tillage, mini-tillage, conventional tillage, bare land, and Contour farming were -31.26, 0.10, 0.40, 0.34 and -1.02, respectively, which meaned that the prediction result was not good. WEPP simulated results for mini tillage, conventional tillage, and bare land were better than the other tillages.5)Compared the predicted results of runoff and soil loss using CLIGEN and BPCDGN, the result showed that WEPP simulated results using BPCDG were better than that using CLIGEN。更多还原