径流及泥沙中7Be含量分布与影响因素研究

通过分析次降雨下,来自坡耕地、荒草地、灌木林地径流小区径流、泥沙中7Be含量,发现径流中7Be浓度较小,均值为0.92 Bq/L,但次降雨过程由于受径流量的影响,随径流流失的7Be量较大。坡耕地小区随径流流失7Be占整个小区7Be流失量的11%~33%,对示踪结果影响较大。与地表土壤相比较,侵蚀泥沙中7Be含量较大,尤其是荒草地和灌木林地小区。坡耕地小区侵蚀泥沙颗粒分选性对泥沙中7Be含量影响不明显,它主要受侵蚀类型的影响,面蚀对侵蚀泥沙中7Be含量贡献最大。

7Be Distribution in Runoff and Sediment and its Influence Factor

The ^7Be content in runoff and sediment from different runoff plots under single rainfall event was analyzed, The result showed that ^7Be concentration in runoff was relatively less than that in sediment and the average value was 0.92 Bq/L, However, the total loss of ^7Be from runoff plots was great because much more runoff discharge was lost from runoff plots. It was estimated that 11% -33 % of total loss ^7Be in the whole cultivated plot ran off with runoff, and this had a great effect on the result of tracing soil erosion. The ^7Be content in sediment was more than that in surface soil, especially in the weed and bush plot. At last, it was discovered that the grain size of sediment did not obviously influence the ^7Be content in sediment, and surface erosion played an important role in the ^7Be content of sediment.