Effect of Land Use Change on Soil Physico-Chemical Properties under Different Land Use System in Arsi Zone, Oromia Region, Ethiopia

The establishment of artificial plantation using Eucalyptus globules in Ethiopia is becoming economically important for improving the livelihoods of small holder farmers. The species are adapted to different soil depths with varied responses to soil physical and chemical properties that have an implication on the proper management of environmentally sensitive areas. However, the sources of variations of soil physical and chemical properties have not been well investigated and documented for most vertisol in Ethiopia. This study was designed to investigate soil physical and chemical properties variations under different land use systems of cropland, grazing land and trees covered area with Eucalyptus globulus plantation at Gusha Temela Kebele, Arsi Zone and Oromia, Ethiopia. A total of 48 composite soil samples with 4 replicates * 3 treatments * 2 sampling plots * 2 at soil depths of 0–10 and 10–20cm were used for laboratory analysis. Some of the soil physical and chemical properties were analyzed and interpreted including soil texture, bulk density), soil moisture content, pH, available phosphorus (available P), soil organic carbon, total nitrogen and carbon to nitrogen ratio (C/N ratio). The results showed that, except in a few cases, all considered soil properties showed significant differences with land use types and soil depths. Soil Bulk density (r=0.0002), soil moisture content (r<0.0001), soil pH (r<0.0001), available phosphorus (0.0002) and soil organic carbon (r<0.0001) were significantly varied with land use types. Textural fractions of sand, silt and clay showed no significant difference with land use types and soil depths. Although not significant, the clay content was slightly higher under grazing land. On the other hand, soil parameters including bulk density, soil moisture content, pH, soil organic carbon and total nitrogen were higher under grazing land than in the rest land use types and significantly varied with respect to soil depths; greater in the lower soil depth except for soil organic carbon and total nitrogen which were higher in the upper soil depth. The textural fraction of clay across all land use types was higher in the lower depth than in the upper surface layer which could be due to the translocation of this fine particle from the upper soil layer to the lower one. Findings of the present study indicated that land use change has more effect on soil chemical than physical parameters that grazing land is more fertile than other land use types. It implies that management practices significantly influence soil chemical properties variations especially the soil organic carbon concentrations for better employment of land management practices through implementation of climate smart agriculture.