UNDERSTANDING SOIL QUALITY, LAND USE CHANGES AND CLIMATE VARIABILITY FOR EFFECTIVE WATERSHED MANAGEMENT, THE CASE OF GOJEB RIVER CATCHMENT, OMO-GIBE BASIN, ETHIOPIA

Abstract

Assessment and understanding of soil qualities (SQ) and the inherent Land use land cover changes are important physical indicators for sustainable land management strategies. On the other hand, soil erosion and adoption knowledge of farmers is fundamental social dimension. Land use land cover (LULC) changes are inherently spatial and dynamic with high spatiotemporal variability resulted from complex human-environmental interactions. The objectives of this study were (i) to assess the effects of land uses and soil and water conservation measures on soil quality indicators; (ii) to investigate farmers’ perception of soil erosion, participation and adoption of soil conservation technologies (SWC) in the Geshy sub-catchment of Gojeb river catchment, Ethiopia; (iii) to assess LULC changes and its drivers; and (iv) to examine the effects of climatic variability (rainfall) on NDVI for the periods 1982-2015in the Gojeb River Catchment, Omo-Gibe Basin, Ethiopia. A total of 54 soil samples (three LU types x three slope classes (blocks) x three replications x two soil depths) were collected with an “X” plot design. Moreover, A total of 54 soil samples (two treatments-farmlands with and without SWC measures*three slope classes*three terrace positions*three replications) were collected at a depth of 20 cm for data analysis. Statistical differences in SQ indicators were analyzed among LU types, conservation measures, slope classes and soil depths and tested using univariate analysis of variance and Pearson’s correlation coefficient following the general linear model procedure of SPSS Version 20.0 for Windows. Additionally, Farmers’ perception of soil erosion, participation and adoption of soil conservation technologies was investigated based on a detailed survey of 77 households using descriptive and chi-square statistics of SPSS version 20 for windows. Means that exhibited significant differences were compared using Tukey’s Honest Significance Difference at a 5% probability level. The results showed that a number of SQ indicators were significantly influenced by LU changes, conservation measures and soil depths. The sand, dry soil bulk density (