RILL EROSION PROCESS ON STEEP SLOPE LAND OF THE LOESS PLATEAU 1

Rill erosion processes and principle of preventing rill erosion of different applied measures are studied by rainfall simulation and field investigation. Research results show that rill erosion processes can be schematically divided into five stages, that is, concentrated flow forming process; little waterfalls in the concentrated flow forming Process; little waterfalls developing into rill head cut process; rill head cuts developing to form discontinuous rill process and discontinuous rills connecting to form continuous rill process. Rill head cuts backward erosion, rill wall collapsing and runoff washing rill bed are the main patterns of rill development. The relevant equation between critical runoff volume of occurring rill erosion and slope degree can be expressed as follows: Q = 76. 10 - 2. 10J. And relevant equation between critical slope length of occurrence Of rill erosion and slope degree is parabolic with a minimum-value. In addition, influence of rill erosion development on slope runoff and soil erosion, benefits and principle of reducing rill erosion amount of mulch, non-tillage system and remained residue, strip alternation of grass and crop, horizontal ditch are also studied.