Research In The Effect Of Terrace Bank Plants On Erosion Prevention In Loss Hilly Region

In order to steady terrace ridges,protect farmland and extend the terraces lifespan,we builded new terrace ridge in Shanbei Ansai, and planted alfalfa and sainfoin on thetop of the terrace ridges.In different growth period,we got the relationship between themount of grass roots and disintegrating quantity through comparative analysisdifferent terrace hedgerows anti-scouring and root characteristics. And study therelationship between the mount of soil aggregates and the mount of grass roots.Weanalysis runoff and the amount of sediment through setting the micro cell.The mainresults showed that:1. In the Loess Hilly terraced ridge, the two terrace hedgerows couldsignificantly reduce the amount of soil disintegration. With the growth of grass,disintegrating quantity decrease with the increase of grass roots amount. Alfalfagrowth conditions better than sainfoin, alfalfa terrace ridge was more adaptable thansainfoin terrace ridge, and alfalfa can increased the ridge cover, steady terrace bank,reduce the amount of disintegration and reduce terrace bank anti-scourbility.2. After the soil into the water, the process of disintegration with ashort-absorbent, exhaust and weight gain. And then began to fall disintegration, thedisintegration process mainly concentrated in the first5minutes.3. The amount of terrace ridge surface soil disintegration is more than otherterrace ridges. With the increase of soil depth,disintegrating quantity decrease with theincrease of soil density without roots terrace ridge.4. The amount of alfalfa and sainfoin terrace ridge soil aggregates werehigher than naked terrace ridge, and grass effective roots can significantly improve≧2mm soil aggreagtes content.5. The foliage and roots of Alfalfa and sainfoin can intercept rainfall andrunoff, reduce surface runoff. Except the effects of human tillage, the sediment loss ofterrace ridge is mainly come from ridge inside slope, and more than the top of the terrace ridge.