两种测定径流小区泥沙量采样方法的比较

径流小区泥沙量的测定是定量研究坡地和小流域水土流失的基础,在土壤侵蚀模型建立和水土流失预测方面有重要的意义.搅拌取样法是目前应用最广的径流含沙量测定方法,但由于所取样本为表层混合样,粗颗粒泥沙含量少,样本代表性较差,测得的泥沙量远小于实际泥沙量.为此,提出了一种改进的取样方法——沉淀取样法.该法的样本为风干若干小时后的泥沙样品,泥沙分布较为均匀,具有一定的代表性,测定的泥沙含量数据精度较高.根据2012—2013年的实测值,将以上两种方法测定的泥沙量数据进行相互对比,并用年终实测数据进行验证,最终得到较为准确的数据.

A comparison study of two sampling methods for sediment content measurement in runoff plots

Measurement of sediment in run off plots is the foundation of quantifying soil loss in the slope land and small watershed. It plays a significant role in developing a soil erosion model and forecasting soil loss. Sampling after mixing is currently most widely used in sediment concentration measurement of run-off. But since the surface layer of mixed sample contains less coarse sediment,the result data of sediment content tends to be much smaller than real values. Therefore,this study aims to introduce an improved method called sampling after precipitating. We can obtain data of higher accuracy using this approach be-cause sediment is well distributed after several hours’drying. Based on the data from 2012 to 2013,this paper compares the sediment content tested with the two methods above and further checks them with the measured data by the end of the year,thus obtaining the accurate data of sediment content.