基于通径分析的陕北黄土坡面径流产沙影响因素

通过对陕北半干旱黄土区16场有径流产沙发生的次降雨数据进行收集,以径流量和产沙量为因变量,植被类型、植被盖度、坡度、坡向、降雨量、降雨历时、场均雨强、I5、I10、I15、I30、土壤密度、土壤稳渗率作为自变量,在进行逐步回归分析的基础上,对影响径流量及产沙量的主要因素进行通径分析,结果表明:1)植被盖度、降雨量、降雨历时、I30、稳渗率是影响径流量的主要因素,径流量、植被盖度、坡度、降雨量、场均雨强、I15、土壤密度为影响坡面降雨产沙量的主要因素;2)降雨历时、降雨量、I30对径流量起到决定性作用,且对径流量产生影响的直接影响因素排序为降雨历时I30降雨量植被盖度稳渗率,而间接影响排序为降雨量降雨历时稳渗率I30植被盖度,决定系数排序为d降雨量·降雨历时d降雨历时·降雨历时dI30·I30d降雨量·降雨量d植被盖度·植被盖度;3)径流量、降雨量、I15对产沙量起到决定性作用。对产沙量影响因素排序:从直接通径系数来看,径流量I15土壤密度降雨量场均雨强植被盖度坡度;从间接通径系数来看,降雨量场均雨强植被盖度I15土壤密度径流量坡度;从决定系数来看,d径流量·径流量d径流量·降雨量d径流量·I15dI15·I15d土壤密度·土壤密度d降雨量·降雨量。 

Factors affecting slope runoff and sediment yield in northern Shaanxi Province based on path analysis

Based on data collected in 16 rainfall events with runoff and sediment yield on semiarid loess area in northern Shaanxi Province of northwestern China, we determined the main factors affecting runoff and sediment yield using path analysis. The runoff and sediment yield were set as dependent variables, while vegetation type, vegetation coverage, gradient, slope aspect, rainfall, rainfall duration, average rainfall intensity, I5, I10, I15, I30, soil bulk density and steady soil infiltration rate as independent variables. All the factors were processed by stepwise regression analysis. The following conclusions were reached: 1) Runoff was mainly affected by vegetation coverage, rainfall, rainfall duration, I30 and steady soil infiltration rate, while sediment yield was mainly influenced by runoff, vegetation coverage, gradient, rainfall, average rainfall intensity, I15 and soil bulk density. 2) Rainfall duration, rainfall and I30 were crucial factors affecting runoff; the factors affecting runoff based on the direct path coefficient were ranked in a descending order as rainfall duration I30 rainfall vegetation coverage steady soil infiltration rate; based on the indirect path coefficient, the order was rainfall rainfall duration steady soil infiltration rate I30 vegetation coverage; based on the coefficient of determination, the order was drainfall·rainfall duration drainfall duration·rainfall duration dI30·I30 drainfall·rainfall duration dvegetation coverage·vegetation coverage. 3) Runoff, rainfall and I15 were critical factors for sediment yield; The descend order of factors affecting runoff based on the direct path coefficient were ranked in a descending order as I15 soil bulk density rainfall average rainfall intensity vegetation coverage gradient; based on the indirect path coefficient, the order was rainfall average rainfall intensity vegetation coverage I15 soil bulk density rainfall gradient; based on the coefficient of determination, the order was drunoff·runoff drunoff·rainfall drainfall·I15 dI15·I15 dsoil bulk density·soil bulk density drainfall·rainfall.