黄土塬区坡面及小集水区泥沙输移比变化特征  

The Change of the Sediment Delivery Ratio From the Slope and Water-Collected Plot in the Gull Region of Loess Plateau

作　　者：赵晓光[1] 石辉[2] 

机构地区：[1]西安科技学院地质与环境工程系,陕西西安710054 [2]西南师范大学资源与环境科学学院,重庆北碚400715

出　　处：《山地学报》2002年第6期718-722,共5页Mountain Research

摘　　要：文章首先推荐了计算泥沙输移比SDR时,所需侵蚀量、输移量的量测方法:侵蚀量用坡长为20 m(水平距)、宽5 m的直线坡,在不同降雨及土地利用下,通过小区出口断面的泥沙量;输移量为坡长大于20m的径流小区或小集水区出口处的拦蓄量。然后通过黄土塬区坡面坡度为9％的30 m、40 m、60 m径流小区9年野外实验所得45组有效数据的分析,发现单宽最小径流率qmin和最大含沙量ρmin可判别坡面泥沙侵蚀与输移的对比关系,即输移比SDR,并依据这些参数值,可将侵蚀输移状态划分为“侵蚀——输移区”,“侵蚀——堆积——输移区”和“侵蚀——输移挠动区”3个侵蚀输移状态类型区。同时通过研究给出了各区之间过渡转换临界值的计算公式,即ρmax=11.96+0.117qmin或qmin=8.187ρmax=-85.676。并通过对21条塬面不同面积(0.5hm2-41.3hm2)、坡长(30 m-965 m)小集水区淤积(输移量)的测量,将测量值与标准小区侵蚀量作对比,计算出各自的输移比SDR,并分别建立了SDR与坡长L、SDR与集水面积A的关系式,即SDR=2.85L-0.306和SDR=0.735A-0.151,为快速估算塬面小集水区泥沙输移比.SDR值提供了方便。最后,分析了植被覆盖、土壤含水状况、人为活动等其它因素对泥沙输移比SDR的影响。Firstly, Methods to measure soil erosion and sediment delivery were introduced when The methods were used to calculate the ratio of sediment delivery. With different condition of rain and land utilization, Soil erosion can be calculated through measuring the sediment at the exit transect of the plot (20 meters long and 5 meters wide); sediment delivery can be gained through measuring the sediment reserving at the exit of runoff plot or small water collection area which slope length is more than 20 meters. Then After 45 group data from runoff plot 30, 40 and 60 meters long, slope gradient 9% for 9 years were analysed, rate of the minimum runoff unit width and the maximum sediment may use to discriminate the comparative relationship between erosion and sediment delivery, e.g. the ratio of sediment delivery. According to these parameter , the erosive delivery status was divided in to three patterns: erosion-delivery plot erosion-sediment trap-delivery plot and erosion-de livery and disturbance plot. The formula for the critical value among the different plot is pmax - 11. 96 + 0. 117qmin and qmin - 8. 187ρmax - 85. 676。 By measuring sediment delivery from different area (0.5hm2 -41.3hm2) and slope length (30m-965m) water-collected plots and comparing erosion amount from standard plot, sediment delivery ratio was obtained. Equation between sediment delivery ratio (SDR ) and slope length or water-collected area is SDR = 2.85L-0.306 or SDR = 0.735A-0.151 , The equation is convenient for rapid calculating SDR. Finally, effects of vegelation cover, soil moisture and mans activity and other fators on the sediment delivery ratio were also discussed.

关 键 词：输移比 黄土塬区 坡面 小集水区 

分 类 号：S151.7[农业科学—土壤学]