アグロテクノロジー

概要

Review of Soil Erosion Risk For Soil and Water Conservation Planning Under Ethiopian Condition

Kedir Jemal

Soil erosion is one of the major factors affecting sustainability of agricultural production in Ethiopia. This paper reviews Ethiopia’s experience and research progress in soil erosion risk for Soil and Water Conservation planning. In most findings conducted at Ethiopian watershed possibilities of high soil lose and risk was reported. Their findings revealed that the study areas are facing different problems such that forest transformation, which is very likely intensified by the demand for subsistence agricultural land. Most of the parts of these watersheds have experienced intensive soil erosion behavior, which is beyond the tolerable soil loss level. This threatens the annual crop production and the productivity of the land impacting the local farmers’ food security. Analysis of a compilation of soil loss rates due to sheet and rill erosion at plot and catchment scales indicates that this soil degradation process varies strongly spatially, with a mean soil loss 29.9 t ha ⁻¹ yr −1.The highest rates were observed in Anjeni (110 t ha ⁻¹ yr −1) and Chemoga (102 t ha ⁻¹ yr −1) of the Upper Blue Nile Basin. Studies in the northern Ethiopian highlands and the Central Rift Valley of Ethiopia reported larger erosive power of rainfall as compared to elsewhere in the world.FAO (1986) estimated of gross annual soil loss nationwide of 1.9 × 10 9 t of which 80% originates from croplands. Hurni (1988) estimated a nationwide annual gross soil loss of 1.5 × 109 t, extrapolating data obtained from six SCRP research stations in which the highest loss is from croplands (42 t ha ⁻¹ yr −1 ). Sonneveld et al. (2011) provided a tentative nationwide mean annual soil loss map combining the results of different model estimates. They stated that soil loss varies remarkably from 0 t ha ⁻¹ yr −1 in the eastern and southeastern parts of Ethiopia to more than 100 t ha ⁻¹ yr −1 in the northwestern part of the country. Hence, review on identifying and prioritizing erosion susceptible areas for soil conservation measures are quite essential. Reviewing or quantifying the effects of the soil loss helps to substantiate investment in sustainable land management for the benefits to land users. Appropriate soil conservation measures bring economic advantages to the land users. Review on amount of soil loss and the status of the existing soil conservation measures can be realistic for farmers and policy makers if expressed in terms of understandable value.