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黄河源区退化草地水土流失规律
引用本文:李国荣[],李希来,陈文婷,朱海丽,李进芳,祁 军,王洪维.黄河源区退化草地水土流失规律[J].水土保持学报,2017,31(5):51-55.
作者姓名:李国荣[]  李希来  陈文婷  朱海丽  李进芳  祁 军  王洪维
作者单位:1. 青海大学地质工程系,西宁810016;青藏高原北缘新生代资源环境重点实验室,西宁810016;2. 青海大学农牧学院,西宁,810016;3. 青海大学地质工程系,西宁,810016
基金项目:青海省科技厅项目(2016-ZJ-728),国家自然科学基金项目(41662023;41762023),国家国际科技合作专项项目(2015DFG31870),教育部长江学者和创新团队发展计划(IRT_17R62),青海大学中青年科研基金项目(2015-QGY-10)
摘    要:为了阐明高寒草甸退化草地水土流失的规律,以黄河源区河南县退化草地为研究对象,采用野外现场原位人工模拟降雨试验方法,对不同降雨条件下土壤径流量、冲刷量随坡度、退化程度、降雨历时和降雨强度的变化规律进行了试验和分析。结果表明:天然退化草甸的含水量及密度均随坡度和退化程度呈递减趋势(P0.05);同等条件下径流量与植被覆盖度呈幂函数负相关关系(y=140.69x~(-0.4667),R~2=0.988 2),与降雨强度呈指数函数正相关关系(y=40.35e~(0.0252x),R~2=0.970 8);泥沙量与植被覆盖度呈指数函数的负相关关系(y=4294.3e~(-0.0418x),R~2=0.990 7),与降雨强度呈指数函数正相关关系(y=62.657e~(0.0201x),R~2=0.968 8);坡度为30°的小区径流量较10°和20°的坡度小区分别增加了3.6倍和1.7倍,泥沙量分别增加了16倍和1.4倍,表明径流量、泥沙量随坡度的增加而急剧增大;植被覆盖度40%以下的区域其径流和泥沙含量变化幅度较大;降雨开始30min内的地表径流量相对稳定,降雨时间30min后地表径流量开始缓慢上升,坡面泥沙流失量主要集中在降雨后的5~15min内,而降雨55~60min后泥沙量急剧降低,因此试验认为降雨历时1h为土壤颗粒流失的敏感期;天然边坡径流产生后坡面出现汇流冲蚀现象,是退化草地水土流失加剧的重要原因。

关 键 词:黄河源区  退化草地  水土流失  人工模拟降雨  冲刷量

Experimental Study on Soil Erosion Rule of Degraded Grassland in Source Area of the Yellow River
LI Guorong,LI Xilai,CHEN Wenting,ZHU Haili,LI Jinfang,QI Jun,WANG Hongwei.Experimental Study on Soil Erosion Rule of Degraded Grassland in Source Area of the Yellow River[J].Journal of Soil and Water Conservation,2017,31(5):51-55.
Authors:LI Guorong  LI Xilai  CHEN Wenting  ZHU Haili  LI Jinfang  QI Jun  WANG Hongwei
Institution:1. Geological Engineering Department of Qinghai University, Qinghai Xining 810016;2. Key Lab of Cenozoic Resource & Env. in North Margin of the Tibetan Plateau, Qinghai Xining 810016;3.College of Agriculture and Animal Husbandry of Qinghai University, Qinghai Xining 810016
Abstract:In order to clarify soil erosion of degraded alpine meadow,the degraded grassland of Henan County in source area of the Yellow River was chosen as research object.Field rainfall simulation experiment in situ was adopted to analyzed the changes of soil runoff and erosion quantity with soil slope,degradation degree,rainfall duration and rainfall intensity under different rainfall conditions.The results showed that:Natural water content and density of degraded meadow soil declined with the slope and the degradation degree(P< 0.05).Under the same conditions,the runoff and sediment yields had negative correlations with vegetation coverage,showing power(y =140.69x-0.4667,R2 =0.988 2) and exponential functions (y =4294.3e-0.0418x,R2 =0.990 7) respectively.Both runoff and sediment yields had positive correlations with rainfall intensity,the correlation functions were y=40.35e0.0252x(R2 =0.970 8) and y=62.657e0.0201x(R2 =0.968 8) respectively.The plot runoff of 30° slope increased by 3.6 times and 1.7 times respectively than 10° and 20° slope,and sediments also increased by 16 times and 1.4 times respectively.These showed that the runoff and sediment yields increased sharply with the increase of slope.The variations of runoff and sediment concentrations were large under the vegetation coverage of less than 40%.Surface slope runoff began to rise slowly after 30 min of rainfall,and the slope sediment loss mainly concentrated in 5 ~ 15 min after rainfall,and the sediment yield was sharply reduced after 55 ~ 60 min of rainfall.Thus,it could be concluded that rainfall duration of one hour was the sensitive period of soil particle erosion.The confluence scouring of hillslope after natural slope runoff was the important reason of aggravate soil erosion in degraded grassland.
Keywords:source area of the Yellow River  degraded grassland  water and soil erosion  artificial rainfall simulation  erosion quantity
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