降雨与植被变化对川中丘陵区典型小流域侵蚀产沙的影响  

Effects of rainfall and vegetation change on soil erosion and sediment yield in typical small watershed in hilly area of central Sichuan Basin

作　　者：付滟 郑江坤[1] 任雨之 王文武[1] 曾倩婷 向明辉 陈鑫 张云奇 赵鹏 FU Yan;ZHENG Jiangkun;REN Yuzhi;WANG Wenwu;ZEN Qianting;XIANG Minghui;CHENG Xin;ZHANG Yunqi;ZHAO Peng(Key Laboratory of Soil and Water Conservation&Desertification Combating of Sichuan Provincial Colleges and Universities,College of Forestry,Sichuan Agricultural University,611130,Chengdu,China;Water and Soil Conservation Experiment Station of Suining City,629006,Suining,Sichuan,China)

机构地区：[1]四川农业大学林学院,水土保持与荒漠化防治四川省高校重点实验室,成都611130 [2]遂宁水土保持试验站,四川遂宁629006

出　　处：《中国水土保持科学》2019年第4期67-74,共8页Science of Soil and Water Conservation

基　　金：水利部公益性行业科研专项“水土保持生态效应监测与评价技术研究”(201501045);中国博士后科学基金面上项目“四川紫色土土壤有机碳流失机理及对碳储量的影响”(2012M511938);国家自然科学基金“华北土石山区典型林分坡地径流形成机制研究”(41601028),“近50a沂蒙山区大型水库泥沙来源及其对流域环境演变的响应”(41671277)

摘　　要：为了解年和次降雨尺度下植被变化对解家湾小流域侵蚀产沙的影响,运用RUSLE模型计算小流域降雨侵蚀力,采用双累积曲线法和分离判别法分析侵蚀产沙变化的成因。根据植被调整和双累积曲线变化,分为农作物种植期(1986—1989)、经果林种植期(1990—2008)和搁荒期(2009—2016);以农作物种植期为基准期,经果林种植期侵蚀产沙量减少了80.24%,其中植被和降雨的贡献率分别为78%和22%,经果林使冠层覆盖增加,根系固土能力增强,并且梯田梗坎可减少产沙。以经果林种植期为基准期,搁荒期侵蚀产沙量增加79.52%,其中植被和降雨的贡献率分别为88%和12%,搁荒期引起的排水不畅会导致梯田梗坎大量溃坏,增加产沙量。流域产沙与植被覆盖大小和梯田埂坎是否完善有直接关系。植被覆盖在一定的降雨侵蚀力区间内减沙作用明显,但超过临界值时,植被减沙作用变弱。增加乔灌层、布设水土保持工程并进行有效田间管护可明显减少侵蚀产沙。[Background]It is found that vegetation plays an important role in soil and water conservation.This paper is to understand the effect of vegetation change on soil erosion and sediment yield in Xiejiawan watershed,a small watershed in hilly area of central Sichuan Basin,under annual and individual rainfall scales.[Methods]Based on the data of rainfall and sediment yield of Xiejiawan watershed over 30 years,RUSLE model was used to calculate the rainfall erosivity of the small watershed.Combined Land-Use and Land-Cover Change(LUCC)with soil and water conservation engineering adjustment,the causes of soil erosion and sediment yield were quantitatively evaluated by the double cumulative curve method and the separation discriminant method during different periods in the small watershed.[Results]1)During 1986-2016,rainfall and erosive rainfall in Xiejiawan watershed occurred mainly in June,July and August which accounted for 80%of that in all the year.Therefore,soil and water conservation projects should be strengthened in summer.2)Interannual variability of rainfall and erosive rainfall were not obvious during 1986-2016,meanwhile,annual mean sediment modulus during 1990-2008 was obviously less than the values during 1986-1989 and 2009-2016.Soil erosion and sediment yield decreased dramatically when LUCC changed from farmland to orchard.The soil and water conservation engineering measures were destroyed seriously when the forest land was abandoned,resulting in the amount of soil erosion increased at initial stage of abandoned period and decreased gradually after the restoration of understory herbs at later stage of abandoned period.According to LUCC and the trend of double cumulative curve,the time period was divided into crop period(1986-1989),orchard period(1990-2008)and abandoned period(2009-2016).3)Taking crop period as the base period,the contribution rates of vegetation and rainfall on sediment reduction were 78%and 22%,respectively when crop was transformed into orchard,which indicated that planting orchard effec

关 键 词：梯田工程 植被变化 双累积曲线 输沙模数 川中丘陵区 

分 类 号：S157.1[农业科学—土壤学]