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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 fertility depletion due to soil erosion and nutrient leaching caused by heavy and continuous rainfall is one of the major causes for declining of soil productivity and crop yields in Masha district of south-western Ethiopia. Soil Hence, a field experiment was conducted in Belg and Meher seasons at Abelo area, Masha district, south-western Ethiopia, to determine the effect of combined application of cattle manure (CM) with inorganic nitrogen (N) and phosphorus (P) on potato tuber yield, and selected soil physico-chemical characteristics. The treatments comprised of combinations of three rates (2.5,5, 7.5 t ha-1) of CM with 25%, 50% and 75% of recommended rates of mineral NP, respectively. In addition, 100% recommended rate of mineral NP (165 kg N ha-1 and 137 kg P2O5 ha-1) and zero rates were used for comparison. The experiment was laid out in a randomized complete block design with three replications. The results revealed that applying 7.5 t ha-1 CM combined with 75% mineral NP gave significantly highest potato total tuber yield of (40 and 34 t ha-1), the same rate increased tuber yield by 55.9% and 43.45% in Belg and by 51.19%, and 36.64% in Meher over the control and the application of 100% recommended rate of NP fertilizers, respectivelysoil pH (5.15 and 4.94), Organic carbon (21.1and 12.7 g kg-1 ), total N (1.71 and 1.51 g kg-1), available P (7.55 and 6.27 mg kg-1), CEC (22.04 and 23.96 cmol (+) kg-1 ), exchangeable Ca+2 (8.36 and 8.28 cmol (+) kg-1), exchangeable Mg+2 (3.14 and 2.06 cmol (+) kg-1), total porosity (51.1 and 54.97%) more over the treatment decreases exchangble acidity (2.32 and 2.08 cmol+kg-1) and exchangble aluminum (1.46 and 1.41 cmol(+) kg-1), bulk density (1.07and 1.30g cm-3)  in Belg and Meher seasons, respectively. Therefore, it can be concluded that the use of combined application of 7.5 t of ha-1 CM together with 75% of recommended rates of inorganic N (123.75 kg N ha-1) and P (103.05 kg P2O5 ha-1). can significantly increase potato tuber yield and improve the soil properties and reduces soil acidity. Keywords: Cattle manure,physico-chemical properties, nitrogen, phosphorus, tuber yield.

The study was initiated to investigate the effects of slow nitrogenreleasing fertilizer (UREA Stabil ) on yield, yield components and nitrogen use efficiency indices of bread wheat at Emba Alaje and Hawzien Districts in Tigray, Ethiopia in 2015 at six farmers' field and arranged in a randomized complete block design with three replications. Treatments were four levels of nitrogen (0, 32, 64 and 96) kg ha −1 . The nitrogen source was UREA Stabil , which is slow N-releasing fertilizer. Conventional urea at the recommended rate (64 kg N ha −1 ) was included as a positive control at both sites. A full dose of UREA Stabil were applied at planting while prilled urea (conventional urea) was applied in two splits 1/3 at planting and 2/3 at tillering. Application of UREA Stabil significantly influenced yield and yield components at both soil types. The highest grain yield was obtained on plots treated with 64 kg N ha −1 in the form of UREA Stabil and prilled urea (conventional urea) in Hawzien and Emba Alaje districts, respectively. The highest nitrogen uptake was recorded on plots treated with 64 kg N ha −1 in the form of UREA Stabil and prilled urea (conventional urea) in Hawzien and Emba Alaje, respectively. Nitrogen uptake, agronomic, physiological and apparent recovery efficiency were significantly influenced by the application of slow-releasing and conventional nitrogen fertilizers at both sites. In Hawzien, the application of slow-releasing N fertilizer in the form of UREA Stabil reduces the amount of N used and application time. Hence, it could be concluded application of slow-releasing fertilizer could be used as an alternative source of nitrogen for wheat production in the study site.

Acidic soils limit the production potential of crops because of low availability of basic cations and excess of hydrogen (H+) and aluminium (Al3+) in exchangeable forms. In the western part of the country such as Assosa and Wellega, soil acidity is a well-known problem limiting crop productivity. A field study was conducted to assess the effects of lime, vermicompost and their combinations on selected soil physico-chemical properties and responses of soybean grown on acidic Nitisols of Assosa area during 2016 and 2017 main cropping seasons. Soil samples were collected from the experimental site before planting and from plots after harvesting. The collected samples were analysed following the standard methods for soil physico-chemical analysis. The treatments were factorial combinations of four levels of lime (0, 1.62, 3.62 and 4.90 t ha-1) and four levels of vermicompost (0, 1.50, 3.00 and 4.50 t ha-1). The results revealed that soil pH increased from 5.31 – 5.86 pH while exchangeable acidity decreased from 5.46 - 2.85 cmol (+) kg-1 with levels of lime and vermicompost (3.26 with 3 and 4.90 with 4.5) t ha-1 respectively, which resulted in improved soil physico-chemical properties. The combined application of lime and vermicompost also significantly improved the yield related parameters of soybean. The maximum grain yield (1.95t    ha-1) was obtained from the combined application of 4.90 ton lime and 3.00 ton vermicompost ha-1 followed by combined application of 3.26 ton lime with 3.00 ton vermicompost ha-1 with non-significant variation. Therefore, the combined application of 3.26 ton lime and 3.00 ton vermicompost ha-1 is a promising alternative amendment for amelioration of acidic Nitisols of Assosa (Amba-12 Kebele) and other similar agro-ecologies for the improvement of soybean production.