Processes and Causes of Accelerated Soil Erosion on Cultivated Fields of South Welo, Ethiopia

Abstract

The processes and causes of accelerated erosion on cultivated fields in the South Welo zone of Ethiopia were assessed on the basis of information collected from field surveys, group discussions and secondary sources. The findings suggest that soil erosion by water on cultivated slopes in the zone is currently proceeding at an average rate of 35 t/ha/year. Comparable if not more intensive soil loss is also taking place due to tillage erosion on the cultivated slopes although no data is available to support this. Three very broad and inter-linked groups of factors were identified as causes for both the water and tillage induced erosion in the zone. The first group comprises the biophysical factors, i.e., the rainfall erosivity, the soil erodibility and the gradient and length of slopes, which raise the vulnerability of the arable land to accelerated erosion. The second group and the real causes of erosion were identified as the cropping and land management factors. In most of the highlands, crop cultivation is carried out without any type of terracing, while about 74 per cent of this land requires application of contour plowing, broad-based terracing, or bench terracing. The third group of factors include the social and institutional factors which not only compel farmers to cultivate fragile environments but also exert strong influence on the type of land management practices the farmers apply on vulnerable soils. The major ones among this group were rapid population growth (and shortage of land), widespread poverty, and insecure land tenure system.




Eastern Africa Social Science Research Review (EASSRR) VOLUME XVI No. 1 January 2000, pp. 1-22