Understanding organic carbon accumulations in soils is crucially essential concerning carbon sequestration, fighting climate change, increasing land productivity, improving soil properties, providing energy to the microbial community, enhancing ecological restoration, and reversing global environmental damage. This study was aimed at assessing the effects of land-use-cover change (LULC) on soil organic carbon (SOC), its' stock potential, and bulk-density (BD) along slope position in the Coka watershed. Replicated soil samples had been collected and composited from 30 cm depth topsoil of five major land use types and three slope positions. This result showed that significantly (P < 0.001) lowest and highest mean of soil organic carbon stock (SOCS) was observed under bare lands (37.835 Mg ha⁻¹) and bushlands (144.582 Mg ha⁻¹), respectively which was the same for SOC concentration. Barelands lose 3.82 times (3.82x) higher SOCS than bushland and 2.68x more SOCS than forestland. Both SOC-stock and SOC showed significant (P < 0.001) differences among slope positions, which were the highest in lower-slope followed by middle-slope, which had 1.8 and 2.6x higher than in middle-slope and upper-slope positions, respectively. Thus, the multivariate-test result divulges that LULC along slope positions has a strongly significant (P < 0.05) main and interaction effect on SOCS in the area. Therefore, the potential contribution of bushland and forestland uses should be improved for SOC sequestration, soil productivity improvement, and environmental protection.

Soil erosion is a serious problem arising from agricultural intensification and other anthropogenic activities which can cause deterioration of soil fertility and productivity. This study aims to estimate total amounts of soil loss using the RUSLE and NDVI models and identify major areas of concern for management interventions through site specific in the Coka watershed, Southern Ethiopia. The RUSLE model required the integration of thematic factors such as rainfall, length and steepness of the slope, land-use and land-cover, soil erodibility, and control practices. These factors were calculated using remote sensing data and GIS. The results indicated that total area coverage from study of watershed under the degree of severity of erosion and priority was 100 t ha^–1yr^–1 (severe). Soil loss rates ranged between 2.33 in bare land and 237.16 t ha^–1yr^–1 in forest. Based on the findings, erosion risk having estimated soil loss (≥ 18 t ha^–1yr^–1) which is above tolerable range for the country containing 73% (2723 ha) from the total area coverage of watershed. Thus, appropriate soil and water conservation practices should be adopted to restore degraded lands and environment by giving attention for erosion hotspot areas.

Land-use changes along slope position can have a major positive or negative impact on soil environment and agricultural productivity. Relevant information to understand the negative effect of land-use change and slope variability on soil property is a vital element to monitor, plan and make the decision to improve productivity and restore the environment. The aim was to examine the effects of land-use-cover-changes along slope position on the selected soil physicochemical properties in the Coka watershed. Soil samples were gathered from 5 nearby land uses, namely forestland, grassland, bushland, cultivated land, and bare-land, and 3 slope positions (upper, middle, and lower slope) at 0–30 cm soil-depth, analyzed in Hawassa University Soil testing laboratory. The results show that the highest field capacity, available water-holding, porosity, silt, nitrogen, pH-value, cation exchange capacity, sodium, magnesium, and calcium were in forestlands and lower-slope. The highest water-permanent-wilting-point, organic-carbon, soil-organic-matter, and potassium were in bushland; bulk density was in bare land while the highest clay and available-phosphorus were revealed in cultivated land and lower slope. Most soil properties showed a positive correlation with each other except bulk density which has a negative correlation with all soil properties. Generally, cultivated land and bare land have the least concentration in most soil properties which indicates of increasing degradation rate in the area. Thus, soil-organic-matter and other yield-limiting nutrients should be improved in cultivated land to maximize productivity by using an integrated implementation of soil fertility management through cover crops and rotation, compost, manures, and minimum tillage; and amending soil pH-value by liming.

Background: Land-use and land-cover (LULC) change is among the dynamic environmental and ecological factors for monitoring and facilitating the developmental strategies to balance conservation and conflict of resource uses. This study aimed to analyze LULC changes that have occurred during 1988-2018 and its prediction for 2040-2060 periods. Methods: LULC changes were analyzed using geographic information system Landsat and predicted by CA-Markov model. Result: The results of this study confirmed that cultivated-land and rural-settlement, bare-land, built-up-area and waterbody have increased at an annual rate of 23.1, 2.2, 0.8 and 1.1 ha/year but forestland, bushland and grassland have decreased at an annual rate of 14.4, 4.1 and 8.7 ha/year, respectively. It is projected that the increase in cultivated-land, bare-land, built-up-area and waterbody but decreases the forestland, grassland and bushland. Expansion of agriculture and deforestation showed increasing trend on both previous and predicted LULC changes with upcoming expansion of bare-land due to major driving factor of population growth. Thus, well integrated landscape planning and reliable predictions for future LULC are needed to reduce the deterioration of environment.

Land use and land cover (LULC) is among fundamental environmental and ecological factors for monitoring, resource management, police making, planning and facilitating the development of strategies to balance conservation, development pressures, and conflicting uses. This study aimed at analyzing LULC changes that have occurred during 1988–2018 and its prediction for 2040–2060 period in Coka watershed, southern Ethiopia. LULC changes were analyzed using geographic information system and predicted by CA-Markov model. Cultivated and rural settlement land, bare land, built up area and water body have increased at an annual rate of 23.1, 2.2, 0.8 and 1.1 ha/year but forest land, bushland and grassland have decreased at an annual rate of 14.4, 4.1 and 8.7 ha/year, respectively. It is projected that cultivated and rural settlement land, bare land, built up area and water body will expand but forest land, grassland and bushland will decrease. Expansion of agriculture and deforestation showed increasing trend on both previous and predicted LULC changes with upcoming expansion of bare land and eucalyptus tree plantation due to major driving factor of population growth. This study highlights the need for well integrated landscape planning, reliable predictions for future LULC and to reduce the deterioration of environment.