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Background: Soil acidity, low soil nutrient status and low nitrogen fixing inoculants as a result of poor soil fertility management practices are the major constraints in soybean production in Assosa Zone, particularly in Assosa and Bambassi districts. Hence, this experiment was conducted to evaluate the effect of bio-, organic and inorganic NPSB fertilizers and lime on soil physico-chemical properties. Methods: During the period 2019-2020 factorial combinations of two bio-fertilizer inoculants [without bio-fertilizer (B1) and SB12 plus MAR1495 bio-fertilizer at their recommended rates of 500 g ha-1 (B2); two organic fertilizers without fresh cattle manure (M1) and fresh cattle manure at 10 t ha-1 (M2); two lime rates without lime (L1) and lime at 5 t ha-1 (L2); two inorganic NPSB fertilizers NPSB at 9.5-23-3.5-0.05 (F1) and NPSB at 19-46-7-0.1 (F2) at their recommended rates for soybean] were laid out in a randomized complete block design with three replications. Bulk density, pH, total nitrogen, available phosphorus, organic carbon and cation exchange capacity were collected and analyzed using SAS software version 9.1.3 and significant mean differences were separated using Duncan's multiple range test (DMRT). Result: Bulk density, pH, total nitrogen, available phosphorus, organic carbon and cation exchange capacity were highly affected (P<0.01) by the interactions of bio-, organic and inorganic fertilizers and lime. Finally, the interaction of SB12+MAR1495, 10 t/ha fresh cattie manure, 5 t/ha lime and NPSB at 19-46-7-0.1 improved the bulk density, pH, total nitrogen, available phosphorus, organic carbon and cation exchange capacity at both districts. [ABSTRACT FROM AUTHOR]

The soil acidity problem is intensified by improper utilization of synthetic fertilizers in addition to other naturally existing causes; thus, it is important to consider effects on soil health beyond seasonal crop productivity. Most widely used sources of soluble phosphate fertilizers cannot perform effectively on acidic soil due to its fixation. Field experiments were conducted on the acidic nitisols of Welmera District in two locations to determine the effects of using lime and different phosphorus fertilizer sources on the soil acidity attributes and nutrient use efficiency of barley crops. Treatments include a factorial combination of 4 different phosphate fertilizer sources (PARP, MOHP, NPSB, and NAFAKA) with 2 application rates (34.5 kg P2O5 ha−1 and 69 kg P2O5 ha−1) and 2 lime application rates computed from soil exchangeable acidity result 404.25 kg·ha−1 and 563.9 kg·ha−1 for on-station and on-farm sites, respectively, with no lime application (1/4th of LR and 0 lime). Partially acidulated rock phosphate as a phosphorus fertilizer significantly improves soil acidity attributes such as exchangeable acidity, present acid saturation, and plant available phosphorus, and also another soil nutrient status is significantly affected by using different phosphorus sources with the lime application. Application of PARP phosphate sources significantly improves soil exchangeable acidity and present acid saturation by 42% and 41%, respectively, over the commonly used NPSB standard sources of phosphorus fertilizer. Using lime with alternative phosphate sources also contributes to more effective nutrient use efficiency and barely yields improvements with a productive acid soil amendment option. Maintaining soil health by using those integrated approaches improves the efficient utilization of scarce unrenewable resources on sustainable bases. [ABSTRACT FROM AUTHOR]

Purpose Soil acidity and nutrients deficiency are the major constraints causing low crop yield and food insecurity in the highlands of Ethiopia. A field experiment was conducted in northwestern Ethiopia during 2018 and 2019 cropping seasons to study effects of compost and lime application on soil properties and wheat yield. Method The treatments consisted of three compost levels (0, 3 and 6 t ha-1) and three lime rates (0, 1 and 2 t ha-1) arranged in a randomized complete block design with three replications. Before planting and after harvest, soil samples were collected from each experimental plot to analyze soil properties. Results Combination of lime and compost significantly (p<0.05) increased soil pH, soil organic carbon, total nitrogen, available phosphorus and exchangeable base cations. In contrast, exchangeable acidity and aluminum levels decreased substantially compared to individual application of amendments. Compared to the control, application of 2 t ha-1 lime, 6 t ha-1 compost alone and their combination increased wheat grain yield by 24.6%, 42% and 97.5%, respectively. Besides, the combined application of compost and lime provided the highest net benefit (1915.90 US$ ha-1), which was noticeably greater than the control (1034.44 US$ ha-1). Conclusion The application of lime and compost in combination is an effective option to curb soil acidity while enhancing soil nutrients availability and crop yields at lower input costs. However, to determine the application frequency, long-term effects of compost and lime in combination on acidic soil properties and crop yield need to be investigated through further research. [ABSTRACT FROM AUTHOR]

Phosphorus (P) transformations and associated changes in soil chemistry following lime application in acidic soils are very determinant to enhance P use efficiency. Thus, this study was conducted to evaluate the effects of different rates of lime on soil P fractions and chemical properties in acidic Luvisols of southern Ethiopia. The lime rates were 0 t/ha (0%), 3.75 t/ha (50%), 7.5 t/ha (100%), and 11.25 t/ha (150%), and incubated for a month with three replications. The soil P fractions analyzed includes soluble P (P-sol), P associated with iron (Fe-P), aluminum (Al-P), calcium (Ca-P), organic part (Org-P) and residual (Res-P). The result indicated that liming significantly (p < 0.05) improved the release of P-sol, Ca-P, and Res-P, and reduced Fe-P, Al-P, and Org-P. The changes in soil chemical properties were also significant. For instance, increased rate of lime enhanced soil pH from 5.3 to 6.5, reduced exchangeable acidity from 1.47 to 0.15 cmol(+)/kg, and increased available P from 2.74 to 8.72 cmol(+)/kg. Yet, the amount of P-sol was found low for plant needs even at a 150% rate of lime. Thus, working on external P requirement to equilibrate the need for plants followed by crop response validation are suggested. [ABSTRACT FROM AUTHOR]

Soil acidity with associated low nutrient availability is one of the major constraints to soybean production in southwestern Ethiopia. Integrated use of lime and acid-tolerant crops is believed to reduce soil acidity and improve crop production. The experiment was conducted in the field condition of Mettu, southwestern Ethiopia during the 2017/18 main cropping season. The experiment comprised fifteen soybean genotypes and two soil amendment (lime and unlimed) treatments arranged in a split-plot design with three replications. For each treatment, four rows were planted per plot; data related to growth, root, nodule, and yield of the crop were collected at a necessary stage for each. Liming and genotype interaction had significantly (P = 0.01) affected all parameters considered except for hundred seed weight and root volume and were affected only by the main effects of genotypes and liming. A significant reduction for most parameters was found on lime-untreated soil than treated soil. Though some genotypes showed higher performance for root, growth parameters, and yield components under unlimed soils; however, gave higher yield and yield components, when grown on lime-untreated with an average yield reduction of 13.7%, due to soil acidity. The maximum grain yield of (1943.93 kg ha-1) was obtained under lime treated acid soil from PI567046A genotype; while the lowest (510.49 kg ha-1) were recorded from SCS-1genotype under the lime untreated acid soil. Genotype BRS268 showed higher yield (1319.83 kg ha-1) under lime untreated acid soil than lime treated acid soil (1143.47 kg ha-1) and showed less reduction percentage for a number of the nodules, root weight, and number of seeds per plant; while PI567046A showed high reduction percentage for yield, biomass, number of pod and seed per plant. A high difference was observed among the soybean genotypes for soil acidity tolerance, which might be further exploited by breeders for the genetic improvement of soybean. Genotype BRS268 had performed better than other tested genotypes under increased soil acidity. selection would be effective to improve soybean genotypes performance on acid soils and identify low Phosphorus tolerant genotype that helps smallholder farmers optimize soybean productivity on acid soils in the study area. HAWASSA-04 variety is the most tolerant among the tested materials. However, further study is required by considering additional genotypes to reach a conclusive recommendation [ABSTRACT FROM AUTHOR]

This study investigated phosphorous (P) sorption characteristics under lime rates, and validated them under field conditions. Soil samples from nitisols and luvisols were taken, mixed with lime(tha−1) at[0,0], [5.25, 3.75], [10.5, 7.5] and [15.75, 11.25], respectively, and incubated for 30 days. It was equilibrated with KH2PO4 at 0, 10, 20, 30, 40, and 50 mgPL−1. The data were tested with Freundlich and Langmuir models. External P requirement (EPR) and changes in chemical properties were evaluated. The field validation on wheat involved rates of P (0, 8.2, 16.4, 24.6, 32.9, and 41.1 kg ha−1) and lime (0, 650, and 1300 kgha−1) in a randomized complete block design with three replications. Freundlich was found the best-fitted model. Freundlich coefficient (Kf) ranged from 212 to 45 mgPkg−1 (nitisols) whereas it was 112.7 to 16.29 mgPkg−1 (luvisols). EPR (kgPha−1) without and the highest lime rate were: nitisols (142.5 and 52.32 kgPha−1) and luvisols (124.84 and 25.94 kgPha−1). Liming reduced EPR by 63.3% (nitisols) and 79.3% (luvisols). Liming increased soil pH from [4.55 to 6.60 in the nitisols, and 5.33 to 6.51 in luvisols]; exchangeable acidity (cmol(+)kg−1) 3.84 to 0.01 nitisols, and 0.72–0.05 luvisols, and available P (mg/kg) 3.2–6.32 nitisol, and 2.74–8.72 luvisols. Furthermore, applying 32.9 kgPha−1 x 1300 kgha−1 lime resulted in grain yield (4345.2 kgha−1) that was 449% more than the untreated crop (791.3 kgha−1). The validation result suggested higher P than blanket P recommendation. It also justifies that excess P or lime alone cannot be a complete solution for P management and increased yield. [ABSTRACT FROM AUTHOR]

Understanding the nutrient dynamics in acid soil is fundamental to carry out proper management. The study was conducted to investigate phosphorus (P) pools and selected properties under different rates of lime for acid nitisols of Farawocha, Southern Ethiopia. Four lime rates incubated for a month in three replications were tested. The lime rates were 0 t/ha (0%), 5.25 t/ha (50%), 10.5 t/ha (100%), and 15.75 t/ha (150%). Lime requirement (LR) for 100% was calculated targeting soil pH of 6.5. Data on the P pools such as soluble P (P-sol) and bounded forms of P with iron (Fe-P), aluminum (Al-P), calcium (Ca-P), organic part (Org-P), residual P (Res-P), and total of P fractions were measured. In addition, changes in soil chemical properties such as pH, exchangeable acidity, calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), boron (B), zinc (Zn), and manganese (Mn) were analyzed. The result showed that total P was 357.5 mg/kg. Compared to nontreated soil, liming at a rate of 15.75 t/ha significantly improved P-sol (34.2%, r2 = 0.88), Ca-P (61.6%, r2 = 0.92), and Res-P (195%, r2 = 0.94); however, it reduced Fe-P (58.5%, r2 = −0.83), Al-P (71%, r2 = −0.97), and Org-P (19.1%, r2 = 0.93). Overall, the P-associated fractions in the soil, regardless of the lime rates, were in the order of Org_P > Res_P > Fe_P > Ca_P > Al_P > P-sol. Liming raised soil pH by 2.1 units (4.5 to 6.6) over nonlimed soil, whereas it reduced exchangeable acidity from 4.18 to 0.23 meq/100 g soil. Available P, Ca, Mg, S, Cu, Zn, and B contents were significantly improved with lime application. However, liming reduced Fe and Mn contents. In conclusion, these findings showed that liming facilitated the release of P from various pools, modified pH and exchangeable acidity, and resulted in beneficial changes for most of the soil chemical properties. [ABSTRACT FROM AUTHOR]

Soil acidity is one of the major constraints for crop production in the highland areas. The finding of a 25% lime application method was recommended to amend the problems. This research was carried to increased productivity of wheat and creates wider demands through strengthening linkages among stakeholders and assesses farmer's perceptions. It was implemented in the 2018/19 rainy season at four selected districts of the Amhara region. Farmers' and clusters were selected in collaboration with agricultural extensions. Soil samples were collected and exchangeable acidity was determined. A total of 15.3 tons of wheat seed and 9.2 tons of lime were used which carried on 230 farmers and 102 hectares. Based on the exchangeable acidity one-fourth of lime was applied. The training was given for 288 trainees and field days were organized for 1715 participants for further dissemination. The mean grain yield and marginal rate of return were 4525 kg ha−1 and 252%, respectively; there was a yield advantage of 90.23% compared to the previous year. The overall results showed that the applications of 25% of lime on wheat production were efficient and the real way out for soil acidity problems due to reduced cost and logistics. This research work proved that the technology tremendously increased wheat productivity in the acidic soils and hence; it must be effectively used in the acidic soils at a larger scales through incorporating in the extension packages to address more farmers to meet the food and nutritional security and improves citizens' livelihoods of the nation. [ABSTRACT FROM AUTHOR]