黄河源区退化草地水土流失规律

发布时间：2018-05-04 03:27

本文选题：黄河源区 + 退化草地　；参考：《水土保持学报》2017年05期

【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。
[Abstract]:In order to elucidate the regularity of soil erosion in degraded grassland of alpine meadow, taking the degraded grassland of Henan county in the source area of the Yellow River as the research object, the field in situ simulated rainfall test method was used to study the soil runoff under different rainfall conditions. The effects of slope degree, degradation degree, rainfall duration and rainfall intensity on scour amount were tested and analyzed. The results showed that the water content and density of natural degraded meadow decreased with slope and degradation degree (P0.05N), and the relationship between runoff and vegetation coverage was negatively correlated with power function under the same condition. The relationship between water content and density of natural degraded meadow was negatively correlated with that of vegetation coverage, and the relationship between water content and density of natural degraded meadow was positive in exponential function with rainfall intensity. The correlation between sediment content and vegetation coverage is negatively correlated with the exponential function. The correlation between sediment content and vegetation coverage is negative correlation. The correlation between sediment content and vegetation coverage is 3.6 times and 1.7 times higher than that of 10 掳and 20 掳slope, respectively, and the relationship is positive correlation with rainfall intensity, y62.657 e1. 0201 脳 10 掳and 20 掳, respectively, with a negative correlation between sediment content and vegetation coverage, and a negative correlation between sediment content and vegetation coverage is found in the area with a slope of 30 掳and a slope of 10 掳and 20 掳, respectively, with a positive correlation with rainfall intensity (Y62.657eN), and the runoff of the plot with a slope of 30 掳is 3.6 times and 1.7 times higher than that of the plot with a slope of 10 掳and 20 掳, respectively. The amount of sediment increased 16 times and 1.4 times respectively, indicating that the runoff and sediment content increased sharply with the increase of slope, and the runoff and sediment content varied greatly in the area with vegetation coverage below 40%. The surface runoff in 30min was relatively stable at the beginning of rainfall, and the surface runoff began to rise slowly after the rainfall time 30min, and the sediment loss on the slope was mainly concentrated in the 5~15min after rainfall, but the sediment amount decreased sharply after 55~60min rainfall. Therefore, it is considered that the rainfall duration of 1 hour is the sensitive period of soil particle loss, and the phenomenon of runoff and erosion on the slope surface after the natural slope runoff is an important reason for the worsening of soil erosion in degraded grassland.
【作者单位】：青海大学地质工程系;青藏高原北缘新生代资源环境重点实验室;青海大学农牧学院;
【基金】：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)
【分类号】：S812.2

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