草类根系对土壤抗冲性的强化效应

INTENSIFYING EFFECT OF HERB ROOTS ON SOIL ANTI SCOURIBILITY

本文以研究草本植物根系密度、根量及土壤抗冲性的剖面特征为基础,首次对不同土层深度根系的减沙效应及提高土壤抗冲性的有效范围进行了定量分析。结果表明,草类根系提高土壤抗冲性的作用与其在剖面中的分布状况的关系极为密切;20cm土层内,根系的减沙效应不受坡度及雨强的影响,减沙效应系数平均在0.82以上。20cm以下土层根系的减沙效应明显降低。根据对不同坡度及雨强下根系提高土壤抗冲性的效应曲线及减沙效应的综合分析,确定出在坡度≤30°、雨强≤4.0mm/min条件下,草类根系密度超过166根/100cm^2时对增进土壤抵抗径流冲剧有极其明显的作用,其根系的有效深度下限值为30cm。

Based on the studies on the profile characteristicts of root density, root weight and soil anti-scouribility, the sidement reduction effect of herb roots and the range of soil anti-scouribility increased by herb roots distributed in different soil layers are first quantitatively analyzed. The results obtained show that the intensified value of soil anti-scouribility by the roots was more closely correlated with the root density than with the root weight. Within top 20 cm soil layer, the effect of sidement reduction was not influenced by slope and rainfall intensity. This effect, however, was evidently weakened with the increase in profile depth. According to the comprehensive analyses of the effect curves of herb roots to increase soil antiscourbility and sediment reduction effects under conditions of different slopes(15°,20° and 30°) and rainfall intensities (0.5, 2.0 and 4.0 mm/min), the density range and lower depth limit of herb roots to obviously increase soil ati-scouribility are proposed.