Soil fertility depletion is emerging as a serious challenge causing low crop yields and food insecurity in Ethiopia. An on-farm experiment was conducted in 2017/2018 cropping season to investigate the effects of combined application of compost and mineral fertilizer on selected soil properties and maize yield in North-western Ethiopia. Treatments were factorial combinations of three rates of Urea/NPSB (0/0, 50/50 and 100/100 kg ha−1) and three rates of compost (0, 5 and 10 t ha−1). The field experiment was arranged in randomized complete block design (RCBD) with three replications. Results showed that combined application of compost and mineral fertilizer significantly (p < 0.05) increased soil pH, organic carbon (OC), total nitrogen (TN), available phosphorus (AP), available sulphur (AS) and cation exchange capacity (CEC) compared to sole mineral fertilizer application and the control. On the other hand, there was significant (p < 0.01) decrease in soil bulk density. Plots amended with 10 t ha−1 compost and 100/100 kg ha−1 Urea/NPSB provided the highest maize dry biomass (18.62 t ha−1) and grain yield (6.07 t ha−1). Conversely, the lowest biomass (5.70 t ha−1) and grain (1.17 t ha−1) yields were obtained from the control. The partial budget analysis also showed that the highest net benefit (32700 Birr ha−1) was obtained from combined addition of organic and mineral fertilizer which was significantly higher than applying the highest rate of sole mineral fertilizer (27438 Birr ha−1), highest rate of sole compost (9011.3 Birr ha−1) and the control (7660 Birr ha−1). Therefore, we concluded that integrated fertilizer management improves soil properties and crop yield in the highlands of north-western Ethiopia.

Soil acidity has become a major constraint that threatens sustainable agricultural production in Ethiopia. This study was conducted to evaluate effects of lime rates and application methods on selected soil properties and wheat (Triticum aestivum, L.) yields on acidic Luvisols of northwestern Ethiopia. The treatments included control, 0.5, 1, 2 and 3 t ha^-1 lime drilled along the seed rows and 2, 3, 6 and 12 t ha^-1 lime applied in broadcasting method. The experiment was arranged in a randomized complete block design (RCBD) with three replications. Lime rates applied for this experiment were quantified using exchangeable acidity and Buffer pH methods. To analyze selected soil properties, composite soil samples were collected immediately before sowing and after harvest. Results revealed that liming significantly increased soil pH, available phosphorus, and exchangeable bases but markedly reduced exchangeable Al³⁺ contents. The lime rates determined by buffer pH method were greater in ameliorating soil acidity, increasing soil nutrients status and crop yields than exchangeable acidity. Besides, lime application along the row was better in overcoming soil acidity constraints and increasing crop yields compared to broadcast application. Application of 12 t ha^-1 lime in the broadcasting method, 3 t ha^-1 and 2 t ha^-1 lime drilling along the row increased wheat grain yield by 65.10, 49.80 and 27.05%, respectively, compared to the control. Likewise, partial budget analysis showed that the highest net benefit (51,537 Birr ha^-1) was obtained from plots amended with 3 t ha^-1 lime while the lowest economic profit (31,627.5 Birr ha^-1) was recorded from treatments that received 12 t ha^-1 lime. Thus, we concluded that application of 3 t ha^-1 lime in row is a promising practice to mitigate soil acidity and increase available nutrients, exchangeable bases and crop yields in the study area and similar soil types elsewhere.

Low soil fertility has become a serious constraint affecting agricultural productivity and food security in North-western Ethiopia. A field experiment was conducted to examine the effects of integrated use of compost and mineral fertilizer on soil properties and tef (Eragrostis tef [Zucc.] Trotter) yields for two years during 2018 and 2019 cropping seasons. The field experiment was arranged in a factorial combination of three rates of Urea/NPSB (0/0, 62.5/75 and 125/150 kg ha⁻¹) and three rates of compost (0, 5 and 10 t ha⁻¹) laid out in randomized complete block design (RCBD) with three replications. Results showed that combined use of compost and mineral fertilizer significantly (p < 0.05) increased soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), available sulfur (AS) and exchangeable bases but significantly (p < 0.05) decreased soil bulk density (SBD) compared to sole mineral fertilizer application and the control. Furthermore, application of 10 t ha⁻¹ compost combined with 125/150 kg ha⁻¹ Urea/NPSB gave the highest tef dry biomass (8.81 t ha⁻¹) and grain yield (2.40 t ha⁻¹). The economic analysis results also revealed that the highest net benefit (45,761 Birr ha⁻¹) was achieved from the same treatment which was considerably greater than the highest rate of sole mineral fertilizer (37,228.5 Birr ha⁻¹), the highest rate of sole compost (6656 Birr ha⁻¹) and the control (5391 Birr ha⁻¹). We concluded that integrated fertilizer application enhances soil fertility, crop yields and generates better income over individual addition of fertilizers.

Soil quality degradation has become a major problem that results in low agricultural productivity and increasing food insecurity in sub‐Saharan Africa. Improving our understanding of how different land uses and slope positions affect soil properties is critical for developing best land management practices. The objective of this study was to examine effects of land uses and slope gradients on physicochemical properties of the soil in the Woynwha watershed, Northwest Ethiopia. Composite soil samples were collected from 0‐ to 20‐cm depth in three major land uses (natural forest, cultivated, and grazing lands) and three slope positions (upper, middle, and lower) with three replications using an auger. In addition, undisturbed soil samples were collected using a core sampler for bulk density analysis. The collected soil samples were analyzed following standard procedures. The variation in soil properties among land uses and slope positions on soil properties was determined using analysis of variance. Means comparison was performed using the least significant difference test at a 5% significance level. The results revealed that land use types and slope gradients showed statistically significant (p < 0.01) differences in sand, silt, clay, bulk density, pH, available phosphorus (Av P), total nitrogen (TN), organic carbon (OC), cation exchange capacity (CEC), and exchangeable bases of the studied soil. The highest mean values of bulk density (1.64 g cm⁻³) and lowest total porosity (37.67%) were measured under grazing lands at steeper slopes. On the other hand, the highest total porosity (64.30%), clay (59.33%), silt (21.33%), soil pH (6.62), OC (3.58%), TN (0.32%), CEC (51.20 cmol_c kg⁻¹), Ca²⁺ (11.27), Mg²⁺ (2.50), K⁺ (1.63), and Na⁺ (0.43 cmol_c kg⁻¹) were observed in the lower slopes of natural forest. The highest (6.0 mg kg⁻¹) and lowest (2.33 mg kg⁻¹) contents of Av P were recorded in croplands of lower slopes and grazing lands of upper slopes, respectively. Hence, we conclude that integrated nutrient management and sound land use planning should be implemented for improving soil fertility and crop productivity in the study area and others having similar environment. However, soil properties variability under different depths and agroecologies needs to be examined through further research.

Soil quality depletion has become a serious challenge causing low crop productivity and food insecurity in Sub-Saharan Africa. Information on effects of tillage depths and maize-legumes intercropping on soil properties and maize productivity under irrigation system is lacking. Hence, we conducted field experiment over two cropping years to examine the impact of different tillage depths and maize-legumes intercropping on soil properties and maize productivity in northwest Ethiopia. Treatments were combinations of three levels of tillage depths (zero, conventional, and deep tillage) and four levels of maize-legumes intercropping (maize + soybean (Glycine max), maize + haricot bean (Phaseolus vulgaris), maize + vetch (Vicia faba) and sole maize as a control), arranged in a randomized complete block design with three replications. Both the soil and crop data were subjected to analysis of variance using statistical analysis system software.Results showed that zero tillage depth (0-5 cm depth) and maize-soybean intercropping in combination provided the highest mean soil pH (5.37), organic carbon (2.51%), total N (0.23%), available P (7.27 mg kg -1 ) and cation exchange capacity (29.18 cmol (+) kg -1 ). Besides, the maximum mean dry biomass (17.52 t ha -1 ), grain yield (7.73 t ha -1 ), thousand-grain weight (416) and harvest index (44%) were achieved from deep tillage combined with maize-soybean intercropping. Based on the findings, we conclude that maize-legumes intercropping under deep tillage depth could be a promising practice to improve crop productivity. However, further longterm research needs to be conducted in varied combinations of tillage depths and maize-legumes intercropping strategies in different agroecological conditions.

Soil fertility degradation has become a major challenge resulting in low crop productivity and food insecurity in sub-Saharan Africa. Indigenous scattered trees such as Acacia abyssinica, Albizia schimperiana, Croton macrostachyus and Olea africana are purposively maintained on farmlands to improve soil fertility and crop productivity. However, there has been limited evidence on the effects of those trees on soil properties. Hence, the study aimed to examine effects of A. abyssinica, A. schimperiana, C. macrostachyus and O. africana trees and radial distances on soil physicochemical properties in Baskura Watershed, Northwest Ethiopia. Soil samples were collected from 0–20 cm depth at three radial distances (under canopy, canopy edge and outside the canopy) of each tree trunk. The collected data was analyzed using analysis of variance. Results revealed significant ( p < 0.05) differences in soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorus (Av P), cation exchange capacity (CEC) and exchangeable potassium (Ex K) among tree species and radial distances. The average values of soil pH (6.36 and 6.25), SOC (3.46 and 2.93%), Av P (10.42 and 8.66 mg kg ⁻¹ ), CEC (38 and 36.66 cmol kg ⁻¹ ) and Ex K (2.34 and 2.31 cmol kg ⁻¹ ) were higher under the canopies of C. macrostachyus and A. abyssinica , respectively. However, the highest TN (0.46%) was recorded under the canopy of A. abyssinica . Moreover, soil nutrients decreased with increasing distance from the tree trunks. The contribution of tree species to soil properties improvement follows the order C. macrostachyus > A. abyssinica > A. schimperiana > O. africana . Hence, integrating indigenous trees such as C. macrostachyusand and A. abyssinica on croplands can improve soil properties and nutrient availability. However, further study need to be conducted to examine effects of tree species on soil properties, litter quality and decomposition dynamics under different agroecological conditions.