Using ~7Be measurement to document contribution rate of sediment from different parts of cultivated runoff plots
Using ~7Be measurement to document contribution rate of sediment from different parts of cultivated runoff plots
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发表时间：
2011
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通讯作者：
Wang Guangqian
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作者：
Wang Guangqian
坡面侵蚀产沙来源的研究对坡面土壤侵蚀研究和水土保持措施的制定具有重要意义，本文结合传统方法，采用7 Be法测定了耕作径流小区不同部位的产沙贡献率，结果表明：坡面侵蚀产沙主要来源于距坡顶0- 2 m的部位，坡面侵蚀产沙主要来源于距坡顶0- 2 m的部位细沟侵蚀产沙主要来源于坡面中下部（距坡顶2- 5 m），坡面侵蚀产沙量主要来源于坡面中部，占细沟侵蚀产沙量的75%以上（距坡顶1- 4 m）。当雨强较大时，片蚀形成的沉积物主要来源于整个样地（例如15°图）15°样地不同部位的泥沙对总侵蚀量的贡献率从坡顶向坡底逐渐增大，表明降雨强度对总侵蚀量的贡献率随坡度的增大而增大，降雨强度对总侵蚀量的贡献率随坡度的增大而增大。根据7 Be的测量结果，计算了一次降雨过程中各样地的SDR，除5°径流样地外，其余样地的SDR均在0.643 ~ 0.979之间，接近于1。
The research of sediment source is significantly important for studying soil erosion and designing soil and water conservation measures on slopes.Combined with traditional methods,using 7Be measurement to document the contribution rate of sediment from different parts of the cultivated runoff plots is conducted in this paper.The sediment caused by sheet erosion was mainly derived from the part of 0-2m away from the slope top,accounting for over 60% of the total sheet erosion amount.The sediment caused by rill erosion was mainly derived from the lower-middle part of the plot slope(2-5m away from the slope top),accounting for over 75% of the total rill erosion amount.The total eroded sediment was mostly derived from the middle-part of the plot slope(1-4m away from the slope top).When the rainfall intensity was high,the sediment caused by sheet erosion was mostly derived from the entire plot(for example 15° plot).The sediment contribution rate of the total erosion amount from the different parts of the 15° plot increased from the top to the base of the slope.It showed that the rainfall intensity was a significant factor for the erosion intensity distribution on the plot slope.According to the results of 7Be measurement,the SDR of each plot was calculated during an event rainfall.The SDR of the plots varied between 0.643 and 0.979 and was close to 1 except the 5° runoff plot.