EXPERIMENTAL STUDY ON RUNOFF AND EROSION PROCESSES ON VEGETATION SLOPE

摘要

It is important for ecology reconstruction to illustrate vegetation impact on slope runoff and sediment production on the Loess Plateau. Runoff, sediment erosion and the hydrodynamic characteristics of the slope with and without vegetation above ground part and moss on six gradients(5°, 10° ,15° ,20° ,25° and 30°) were studied. The results showed that, plot runoff volume and coefficient with grass aboveground part and moss(GAM) were a little larger than those without grass aboveground part and moss(NGAM) (except 5° slope). Runoff volume of two treatments on 10° plot were greater than that on the other gradients, while runoff coefficient and sediment rate yield increased with gradient. Average flow velocity of GAM plot was clearly less than NGAM on all gradients. Flow velocity of GAM increased with gradient, while NGAM slope velocity of flow .increased first, then decreased with the maximum on 25° slope. There was little difference on flow Reynolds numbers between GAM and NGAM plot. Runoff flow mainly belongs to laminar and tranquil flow condition for GAM plot and torrent condition for NGAM plot.