Soil Erosion by Tillage in Rainfed N-W. Egyption Coast

Abstract

Tillage erosion is one of the main causes of land degradation. The objective of the present study is to evaluate the effect of tillage systems (up and downslope and contour tillage), soil conditions (consolidated and loosened soils), tillage depth, speed and slope on tillage erosion rate. Field experiments of variable slopes (3-16%) were established on sandy soil of Wadi El Ramala, west Mersa Matruh City. Soil translocation as affected by tillage systems and soil conditions were examined. In addition, soil losses by tillage erosion and water erosion were measured and evaluated. The experimental results showed that the average displacement distance is a function of gradient slopes, soil condition, tillage system, depth and speed. The validation of the soil translocation model developed by (Van Muysen et al 2000), under different gradient slopes, tillage depth, speed and soil condition were evaluated. This validation showed that variations in tracer displacement distance can be successfully predicted. Consequently, such model can be used under sandy soil. Finally, experiment results showed that tillage operations with a chisel plow under present agricultural practices are responsible for the major field redistribution of soil. Furthermore, it is clear that tillage of a loosened soil is far more erosive than tillage of a consolidated soil, where the tillage transport coefficient (K) was 105 kg.m-1 per tillage operation for consolidated soil and 179 kg.m-1 for loosened soil under contour tillage. However, 256 kg.m-1 per tillage prevailed for consolidated soil and 454 kg.m-1 for loosened soil under up and downslope tillage treatments.