Jatropha Curcas L. for Rehabilitation of Degraded Land of Gilgel Gibe Watershed, South Western Ethiopia

Abstract

Decline in soil fertility has become a serious problem affecting all spheres of social, economic and political life of the Ethiopia population. As the result agricultural productivity has been declined from years to years. Some tree/shrubs species are integrated to the farming system to rehabilitate degraded land. One of such species which are commonly integrated with farming system is Jatropha. The overall objective of this study was to assess the role of Jatropha curcas to rehabilitate soil fertility. To achieve the objective, Melka Leku sub watershed was selected from Oromia regional state. Soil samples were collected by using stratified sampling method at depth of 0-30cm from land with   Jatropha and adjacent land without Jatropha plant. For each land use, sites were divided into three slope categories; at each slope three replicates were used. The result of the study revealed  that, all selected soil physico-chemical properties (texture, BD, MC, pH, EC, OC, OM, TN, AvP, CEC, basic cations and PBS) measured under land with Jatropha was significantly different (p< 0.05) from that of  land without Jatropha. Soils under land with Jatropha were superior for all selected soil fertility indicators than adjacent land without Jatropha except BD, sand and silt fractions. The mean values of soil clay, pH, OM, TN and AvP of land with Jatropha and adjacent land without Jatropha site were 54.44 and 37.67%, 6.58 and 5.67, 6.91 and 3.17%, 0.41 and 0.27%, and 18.93 and 14.18 ppm, respectively. The land use interaction by slope positions were significance (p< 0.05) difference for measured soil parameters except for mean value of bulk density, silt and sand at three slope under land with Jatropha and upper and middle slope of adjacent land. Therefore, Jatropha plantation has promising potential to play a decisive role on rehabilitating degraded soil fertility of the study area.

Keywords: Land degradation, Soil Fertility, land rehabilitation and Jatropha curcas L.