Land-use changes under poor management practices are among the major causes of decline in soil fertility and agricultural productivity in south-central Ethiopia. Therefore, the study of soil properties variations across land-use types will have implications for planning proper soil management strategies. This study assessed the effects of land-use types on soil physicochemical properties in the Cheha district, south-central Ethiopia. Seven land-use types, eucalyptus plantation, cultivated, grazing, shrub, enset (Ensete ventricosum), khat (Chata edulis), and natural forest, were considered in describing soil fertility. A total of 21 soil samples (0–20 cm depth) were collected randomly from three representative soil sampling plots across each land-use type and examined for their analysis of soil physicochemical properties. Results showed that land-use changes induced significant (p < 0.05) differences in the soil OC, total N, CEC, pH, aluminum saturation, and Fe among land-use types were observed. Soils under eucalyptus plantation were considerably low in the sand (23.44%), silt (24.00%), and available water content (111.13 mm/m), whereas high in clay (52.56%) content and bulk density (1.39 g cm⁻³) as compared to enset land-use type. Compared to natural forest, soils under enset land-use type were high in soil OC (2.41%), total N (0.23%), and CEC (37.61 cmol (+) kg⁻¹) followed by khat land-use. Correlation analysis also showed a highly significant positive relationship between soil OC and CEC but negative with bulk density, soil pH, and aluminum saturation. Total N in eucalyptus plantation, cultivated, khat, and enset lands were depleted by 56.0%, 40.0%, 36.0%, and 8.0%, respectively. Relative to forest land, lower exchangeable Ca, Mg, and Na contents were recorded in soils of cultivated land use. The extractable Fe, Mn, and Zn contents of soils were generally high and are not limiting for crop production. The intensive exploitation of land resources and improper soil management systems in the area could be the major factors for variations in soil properties across land-use types. Therefore, there is a need to develop integrated soil management practices that could help to restore soil nutrients and thereby minimize the continuing soil degradation for sustainable agricultural productivity.

Soil erosion and sediment yields are the current limitations and future threats to agriculture, water resources and hydropower projects particularly in developing countries. Estimating the extent and comprehending the spatial distribution of hotspot area is crucial to implement evidence-based soil and water conservation (SWC) measures with limited resources. The study used RUSLE and SDR models in ArcGIS 10.8 environment. The RUSLE model was found to be highly sensitive to C factor followed by LS factor. The result indicated that the annual soil loss varies from 0 to 359.99 t ha⁻¹yr⁻¹ with 22.31 t ha⁻¹yr⁻¹ as a mean annual. Besides, the estimated sediment yield ranged from 0 to 42.5 t ha⁻¹yr⁻¹ with a mean value of 12.02 t ha⁻¹yr⁻¹. The finding revealed that the central west (SW_5) and northeast (SW_4) parts of the watershed yield higher sediment. The result also signified that about 52.9% of the eroded materials including soil and nutrients are transferred to the outlet. The outcome of our finding undoubtedly aids in the identification of hotspot areas for the adoption of appropriate SWC measures. Hence, adopting RUSLE and SDR for Gununo watershed and another watershed having similar biophysical and environmental factors is suggested.

Soil organic carbon contents are expected to vary from place to place because of variation in soil properties. However, the extent of variability has not been explored in the study area. This study has, therefore, been initiated to assess the spatial variability of soil organic carbon stock in Gurje subwatershed Hadiya Zone, Southern Ethiopia. A total of 40 randomly predefined sampling points were identified for soil sampling using GIS and a total of 80 composite soil samples and 80 core samples were collected from those points at two sampling soil depths (020cm and 2040cm). The ordinary kriging (OK) method was used as a geostatistical tool and applied to model the spatial variability of soil organic carbon in this study. With respect to soil depth, the coefficient of variation (CV) for SOC and SOCS varied from 40.87 to 51.36, which indicated moderate variability in the study area. For the land use types, the CV varied from 7.94 to 42.06, indicating low to moderate variability for the variables in the study area. The exponential semivariogram model described the spatial structure of SOC at 020cm depth while the spherical one was used for SOCS. Moreover, the exponential model was best suited for SOCS at a soil depth of 2040cm, while the circular model was appropriate for SOC at this depth. The nugget/sill ratio (C0/C0+C) of SOC and SOCS varied from nil to 15.58, reflecting a strong spatial dependence, which could be mainly due to the influence of intrinsic factors (e.g., natural variations in soils) in the study area. Overall, the spatial distributions of SOC and SOCS were higher in the northwestern and eastern parts of the subwatershed.

Low soil fertility and climate change-induced low soil moisture are major problems constraining potato (Solanum tuberosum L.) production in the eastern highlands of Ethiopia. Climate events are projected to become more pervasive. Therefore, research was conducted with the objective of analyzing smallholder potato farmers’ adaptation strategies to cope with the issues of low soil fertility and low soil moisture that are exacerbated by climate change. The research involved surveying eight purposively selected peasant associations in four major potato-producing districts in east and west Hararghe zones. The survey employed a multistage sampling procedure. Data were collected from 357 households using a standard questionnaire, focus group discussions, and key informant interviews. The data were analyzed using descriptive statistics, index ranking, and analysis of variance for survey data. The observed climate data for the period of 1988 to 2017 were analyzed. The Mann-Kendall trend test, standard anomaly index, precipitation concentration index, and coefficient of variation were used to analyze the observed climate data. The survey results revealed the farmers, on average, applied 159 kg urea, 165 kg NPS (63 kg P₂O₅, 31 kg N and 12 kg S), and 1.8 ton of farmyard manure per hectare for producing potatoes. Most smallholder farmers (68.91%) used supplemental irrigation for potato production during the main growing season. The method of irrigation the farmers used was overwhelmingly the furrow method (92.72%). Analyzing the climate data showed that the mean annual temperature increased whereas the mean annual rainfall decreased during the 30-year period. It was concluded that climate change is markedly affecting potato production; in response to this, most of the farmers used supplemental irrigation to cope with moisture stress, all of them applied mineral fertilizers, and some of them additionally applied organic fertilizer to alleviate the problems of soil degradation and nutrient depletion. This implies that soil moisture and nutrient stresses are the major problems constraining potato production against which the farmers need policy and institutional supports to consolidate their coping strategies and build resilience against climate change.

Understanding the influence of land use types and topographic positions on soil physical and chemical properties is vital for sustainable soil management. Therefore, this study was initiated to assess the selected physicochemical properties of soils under different land uses and topographic positions in the subwatershed. The subwatershed area was divided into three land use types (cultivated, grazing, and fallow) and topographic positions (lower, middle, and upper). A total of 27 composite soil samples were collected from (0–20 cm) depth for analysis. All analyzed selected soil physicochemical properties were significantly different by using the least significance difference (LSD) test ( ) for each type of land use, except for soil texture, C/N, and percent base saturation (PBS). The soil textural classes of all land-use types at each topographic position were clay loam. Overall, the results indicate that most of the selected soil physicochemical properties were lower in soils of cultivated land at each topographic position, signifying that management of soil fertility is required to make agriculture sustainable in subwatershed.