International Journal of Agricultural Science Research Vol. 4(1), pp. 001-012, January 2015 ISSN 2327-3321 ©2015 Academe Research Journals

Full Length Research Paper

An assessment of spatial analysis of erosion risk in Shafe watershed, Western Hills of Lake Abaya, South Western Ethiopia

Teshome Yirgu Bayu

Department of Geography and Environmental Study, Arba Minch University, P.O. Box: 21, Arba Minch, Ethiopia.

E-mail: tebayu2013@gmail.com, teshomeyirgu_bayu@yahoo.co.in.

Accepted 20 November, 2014

Abstract

The study area is among the most affected parts of Ethiopian highlands that suffered from soil degradation of varying degrees, over grazing and siltation resulting from inappropriate land use practices, and historic settlement. This paper tried to predict rate of soil loss and regionalized erosion risk areas in intensive farming mountainous environment of Shafe watershed. Universal Soil Loss Equation (USLM) and Geographic Information Techniques (GIS) were used to map and estimate mean annual soil loss in the area. Laboratory analysis of soil revealed, except in the homestead plots, that total nitrogen and organic matter content of the soil was low and progressively decreasing from the homestead. Mean annual soil loss in the study area ranged between 0.04 t and 70 t ha^-1 y^-1. Low to moderate erosion hazardous areas were found in south and central part, while high to severe erosion risk areas were concentrated in the intensively cultivated hilly northern localities. More than a third of the study watershed (32.8%) was categorized under high to severe erosion risk area with soil loss rate ranging between 30 t and 70 t ha^-1 y^-1.

Key words: Watershed, soil erosion, universal soil, loss equation, geographic information system.