坡耕地细沟侵蚀的发生、发展和防治途径的探讨

在坡面股流的流程上，当径流侵蚀力增大到足以冲刷土块，形成小跌水，进而演化为细沟下切沟头时，细沟侵蚀就开始发生了。下切沟头的下切侵蚀和下切沟头间径流对沟底的冲刷、沟头的溯源侵蚀、沟壁的崩塌形成了断续细沟。而一条股流的流程上多个断续细沟溯源侵蚀的连接，就形成了连续细沟。在这个过程中，由于降雨径流侵蚀力和土壤抗侵蚀力在时空上的强弱对比关系，出现细沟的分叉、合并及连通现象。所有这些过程，不但进一步促进了细沟的发展，而且随之造成严重的细沟侵蚀。

Approach to the genesis and development of rill erosion on slope land and the way to control

his paper has analysed genesis and development of rill erosion and its control measures on slope land based on simulated rainfall and field investigation data. It is considered that in the detachment flow-way of slope surface, as the runoff erovisity is great enough to wash soil lump and to form waterfalls, further the waterfalls evolving into headouts in rill, rill erosion occures and develops. Unconnected rills are formed by downward erosion of headcuts and runoff washing to rill bottom between headcuts, drawing back of the headcuts and collapsing of the rill wall. Thus the connection of many unconnected rill headcuts drawing back forms connected rill in a flow way of the detachment flow. Meantime, merging and connecting of the rills happen because rainfall and runoff erovisity is more or less than soil erosion durability to change in time and space. The above process not only further promotes genesis and development of rill, but also creates severe rill erosion.It is considered that zero-tillage and remained residue and mulch on the summer fallow land, level ditch cultivation and strip alternation of grass and agricultural crope on the crope land, steep-slope farmland retired and forest and grass planted are effective control measures of rill erosion.