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This study aimed to determine the spatial variation of topsoil properties as influenced by slope aspects and vegetation types. Three vegetation types and two slope aspects were considered. Disturbed and undisturbed samples were taken from the top soils. A two-way analysis of variance was used to test significant mean differences (α = 0.05). Results showed that contents of bulk density, total porosity, organic matter and exchangeable magnesium were significantly different with changes in slope aspect ( P < 0.05). Textural classes, organic matter, available phosphorus, carbon-to-nitrogen ratio, cation-exchange capacity, per cent base saturation and exchangeable bases demonstrated significant variation among vegetation types ( P < 0.05). The south-facing aspect and the grass vegetation showed higher bulk density but lower organic matter and total porosity. As a remedy for the identified problems, there is a need to undertake plantation of indigenous trees. [ABSTRACT FROM AUTHOR]

Climate analysis at relevant time scales is important for water resources management, agricultural planning, flood risk assessment, ecological modeling and climate change adaptation. This study analyses spatiotemporal variability and trends in rainfall and temperature in Alwero watershed, western Ethiopia. Our analysis is focused on describing spatial and temporal variability of rainfall in the study area including detection of trends, with no attempt at providing meteorological explanations to any of the patterns or trends. The study is based on gridded monthly rainfall and maximum and minimum temperature data series at a resolution of 4 × 4 km which were obtained from the National Meteorological Agency of Ethiopia for the period 1983–2016. The study area is represented by 558 points (each point representing 4 × 4 km area). Mean annual rainfall of the watershed is > 1600 mm. Annual, June–September (Kiremt), March–May (Belg) rainfall totals exhibit low inter-annual variability. Annual and October-February (Bega) rainfalls show statistically significant increasing trends at p = 0.01 level. May and November rainfall show statistically significant increasing trends at p = 0.01 level. March shows statistically significant decreasing trend at p = 0.1 level. The mean annual temperature of the watershed is 25 °C with standard deviation of 0.31 °C and coefficient of variation of 0.01 °C. Mean annual minimum and maximum temperatures show statistically non-significant decreasing trends. Bega season experienced statistically significant deceasing trend in the maximum temperature at p = 0.01 level. The year-to-year variability in the mean annual minimum and maximum temperatures showed that the 2000s is cooler than the preceding decades. Unlike our expectations, annual and seasonal rainfall totals showed increasing trends while maximum and minimum temperatures showed decreasing trends. Our results suggest that local level investigations such as this one are important in developing context-specific climate change adaptation and agricultural planning, instead of coarse-scale national level analysis guiding local level decisions. [ABSTRACT FROM AUTHOR]

Background: Assessment of soil loss rates is crucial to sustainably enhance the benefits of land resources and diminish the adverse impacts of land degradation thereby areas requiring immediate soil erosion management practices can be identified. The study aimed to examine the impacts of land cover dynamics on the spatiotemporal patterns of erosion hotspots. RUSLE factors were produced using GIS and remote sensing techniques.Results: The RUSLE model adapted to Ethiopian conditions was run for 2004 and 2014 where input data layers were overlaid. The results of the model showed clear patterns of changes characterized by gradual shifting of one erosion soil loss severity class into next higher class. There was a net increase in the total soil loss largely under the very high, low and very low soil loss severity classes by 8%, 21% and 9% despite a decline in other severity classes, respectively. It also revealed that more than two-third of the catchment has experienced soil losses rates higher than the tolerable value reported for Ethiopia over which agriculturists should be concerned.Conclusions: Therefore, the observed soil loss rate and sediment yield in the study catchment would lead to further ecological deterioration unless site-specific participatory watershed management practices are employed. [ABSTRACT FROM AUTHOR]