Land Suitability Assessment For Agricultural Land Use By Using Geospatial Technology: A Case Of Arsi Negele Wereda

Abstract

Improper land use planning is the key factor of soil erosion which declines agricultural productivity and food security. Hence, in order to improve agricultural productivity the adoption of land suitability evaluation for agricultural use is essential for sustainable land resource management and soil erosion control in the study area. Therefore, the main objective of this study is to assess agricultural land use suitability in the study area by using geospatial technology. Sentinel 2A satellite image, ALOS DEM, Metrological and soil data were used as input data sets to generate factors for land suitability Assessment and RUSLE factor value for soil erosion. Land suitability for rain fed agriculture was generated from 12 factors such as; Slope, soil depth, soil texture, soil drainage, LULC, PH, soil erosion, temperature, rainfall, EC, CEC and SOC were used as major criteria. Likewise, land suitability for surface irrigation was generated by the same procedure with land suitability for rain fed agriculture regardless of rainfall factor. Soil erosion risk was generated by using 5 factors namely; Rainfall erosivity (R) factor, soil erodibility (K) factor, slope length and slope steepness (LS) factor, cover management (C) factor and conservation practice ( P) factor. Raster calculator in Arc GIS10.8 software was used to interactively calculate annual soil loss and generate soil erosion risk map in the study area. The result showed that the study area land suitability for rain fed agriculture comprises an area of 9.9% (15993.17 ha) highly suitable (S1), 25% (40405.67ha) moderately suitable (S2) and 35.8 (57324.4ha), 29.3 (46618.17ha) marginally suitable and permanently not suitable (N2), respectively. Land suitability for surface irrigation comprise an area of 4.2% (6724.2 ha) highly suitable (S1), 70.4% (112793 ha) moderately suitable (S2) and 25.4(112793 ha) not suitable (N) for surface irrigation. The spatial distribution of annual soil loss varied from 0 to 71.95 t/ha/year. Based on the level of soil erosion rates, the study area classified into five priority categories such as 5.62% (136450.787 ha) severe, 2.23% (7698.99 ha) very high, 2.28% (3659.94 ha) high and 4.8 % (3542.72 ha), 85% (3988.99 ha) moderate and low erosion risk class, respectively. Based on soil erosion categories from moderate to severe soil erosion conservation practice of soil erosion highly recommended before further soil erosion or the erosion turning to no return.