对径流小区泥沙量测定中采样方法的探讨

Study of the Sampling Method for Sediment Content Measurement in the Runoff Plots

径流小区泥沙量测定,是坡地和小流域进行水土流失定量研究的基础,在土壤侵蚀模型建立和预报中具有重大的意义。搅拌取样法是目前应用最广的传统含沙量测定方法,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,本研究提出了一种新的取样方法—沉淀取样法,该法的样本为沉淀且风干若干小时后的湿泥样,湿泥样分布较为均匀,样本具有一定的代表性,测定的泥沙含量数据精度较高。将以上二种方法测定的泥沙量数据相互对比,并用年终实测数据进行验证。

The sediment content measurement is the foundation of quantitative study to the soil erosion on the slope land and in the small watershed, playing a significant role in establishment of soil erosion and prediction model. The method of sampling after mixing is currently the most widely used method in sediment concentration measurement. However, the surface of mixing sample contains less coarse sedimentwith the poor representative, resulting inthe data of sediment content much lower than the real values. Therefore, this research brought forward a new sampling method that is the method of sampling after precipitating. After precipitating and air drying for some hours, the sample of wet mud has the more uniform and the common characteristics, so that the data of sediment has thefeatures of high precision. The mutual contrast was conducted to the data of sediment content collected by the above two methods, and was verified by the yearend measured data.