Integrated soil fertility management could be a useful tool to maintain and improving soil fertility. Therefore, the experiment was conducted with the objective of investigating the influence of biochar, farmyard manure, and mineral nitrogen fertilizer on soil chemical properties. The disturbed soil samples were collected from five locations of each plot at optimum moisture conditions to a depth of 20 cm at the start of the experiment, after six months of farmyard manure and biochar treatments application. The treatments consisted of two levels of farmyard manure (0 and 6 tons ha-1), three levels of biochar (0, 5, and 10 tons ha-1) and three levels of nitrogen (0, 23 and 46 kg N ha-1). The results revealed that the interaction effects of biochar, farmyard manure, and mineral nitrogen fertilizer significantly (P<0.001) influenced the soil chemical properties of major contents of soil available potassium, nitrate nitrogen and ammonium nitrogen after six months. Similarly, the analysis of variance showed that the interaction effect of biochar and farmyard manure levels significantly (P<0.05) influenced soil reaction (pH) and CEC. However, the interaction effect of biochar, farmyard manure and nitrogen levels and that of farmyard manure and biochar levels as well as biochar and nitrogen levels on soil available phosphorus were non-significant. Generally, the availability of plant nutrients concentration in the soil solution before treatments of farmyard manure and biochar application was lower than that of after six months. Likewise, farmer should be advised to add small amount of mineral fertilizer to farmyard manure and biochar to improve soil properties and enhance soil productivity and quality.

Optimum nutrients are basic for proper and balanced fertilizer recommendations as paramount importance in order to confirm food security and increase crop productivity in a sustainable way for farmers and other stakeholders. Soil test based crop response phosphorus calibration study for bread wheat at kofole district in 2016 with objectives to determine the optimum nitrogen of bread wheat to nitrogen-fertilizer applications in soils and to give quantitative guidelines and recommendations of nitrogen-fertilizer for bread wheat on Eutric Vertisols. The study was conducted on farmers’ fields across the district. The treatments considered for optimum nitrogen determination were four levels of nitrogen (0, 46, 69 & 92) and phosphorus (0, 23, 46 & 92) fertilizer included in the treatments. The treatments were arranged in a factorial combination of complete block design with two replications. The plot size of 5mx4m with a seed rate of 150kg/ha a variety of Ogolcho which had been recommended for the area was used. The analysis of variance showed that there were significant differences (p<0.05) among treatments application for all locations. The highest grain yield was obtained on the application 69N kg/ha with no application of phosphorus fertilizers on Eutric Vertisols. Minimum grain yield was obtained on the control plots at all sites. Optimum determination with the partial budget analysis made using the annual average bread wheat grains prices showed that 69 kg N ha-1 gave a marginal rate of return of 122.41%, which is above the acceptable minimum rate of return. Therefore, future research should focus on soil test crop response based phosphorus calibration study of on the result optimum nitrogen of the farmland could be a pre request of the technology before to the end user.

Water quality concerns have been very crucial because good quality water supplies in abundance and readily available for production and productivity is of great importance. Therefore, the study was conducted to assess irrigation water quality of the lowlands of Delo Menna and Berbere districts. The samples were collected from the upstream and downstream of the canals along the farms of the districts during the medium and low peaks of the rivers' flow. About 1 L of water sample was collected from each site. Likewise, the sampling date was on the 15th of designated months. Accordingly, the results reveal that the surface irrigation water has less salinity, sodium hazard and residual sodium carbonate hazard in the irrigated canals and canals along the farms. The electrical conductivity ranges from 0.17 to 0.49 ds/m at lower peak and from 0.06 to 0.24 ds/m at medium peak in Delo Menna district. Moreover, the residual sodium carbonate ranges from 1.34 to 2.57 at lower peak flow and 0.79 to 1.30 at medium peak flows; sodium concentration ranges from 0.36 to 0.46 meq/L at lower peak of the river flow and very small concentrations at the medium peak flow period in Berbere district. The salinity indicator parameters such as all cations and anions, total dissolved solid, adjusted sodium ratio, residual sodium carbonates in the irrigated rivers were low in Delo Menna and Berbere. Therefore, the rivers in both districts are normal for agricultural production of all types of crops which are grown in the low lands of Bale.

The study was conducted for two years on farmers’ fields in Nagelle Arsi District in 2018/19 to 2019/20 to evaluate the effect of rates of NPS fertilizer on growth, yield and yield components of bread wheat and to determine economically appropriate rate of NPS fertilizer for bread wheat production. The experiments were laid out in randomized complete block design (RCBD) with two replications with a plot size of 5 m x 4 m accommodating 20 rows each spaced 20 cm. Spacing of 1.0 m and 0.5 m were maintained in between adjacent blocks and plots, respectively. The treatments consist of 100% Pc from TSP fertilizer and 100, 75, 50, 25% Pc from NPS fertilizer and control (no fertilizer application) on a bread wheat variety Ogolcho with seed rate of 150 kg ha-1. Weed and yellow rest were managed by pallas and rexcido, respectively. The effects of NPS fertilizer rate on mollic andosols was highly significant with phosphorus critical and requirement factors (p<0.01) on plant height, aboveground dry biomass and grain yield whereas spike length, seed per spike and thousand kernels weight were not significant. Also, the effects of NPS fertilizer rate on eutric vertisols was highly significant with phosphorus critical and requirement factors (p<0.01) on spike length, seed per spike, aboveground dry biomass and grain yield whereas the plant height and thousand kernels weight were not significant. The highest grain yield was obtained in 100% pc TSP with recommended rate of 46 kg N ha-1 followed 100% pc NPS with recommended rate of 46 kg N ha-1. The lowest yield (2468 kg ha-1) was obtained in control. The partial budget analysis showed that the maximum net benefit with an acceptable marginal rate of return (MRR) was obtained from 75% pc NPS fertilizer and supplemented rate of 69 kg N ha-1 application on eutric vertisols and 100 % pc NPS fertilizer and supplemented rate of 46 kg N ha-1 application on mollic andosols.

Nowadays, a balanced fertilizer recommendation is of paramount importance in order to confirm the security and sustainably increase crop productivity for farmers and other stakeholders. Soil test crop response based phosphorus calibration study in two years (2017 and 2018) was done for bread wheat in kofele district with objectives to assess and evaluate yield response of bread wheat to phosphorus-fertilizer applications in soils that have initial high/medium/low levels of phosphorus on Eutric Vertisols. A composite soil samples collection were made in zigzag method from farmer’s land and analyzed for available P in order to identify the level of the required parameters in the soil to select farmland for actual experiment. Accordingly, phosphorus calibration study treatments include application of 0, 10,20,30,40 and 50 kg P ha-1 with recommended nitrogen 69 kg N ha-1 with RCBD design was used with two replications. The plot size of 5mx4m with a seed rate of 150 kg ha-1 and Ogolcho variety which had been recommended for the area was used. So that the result showed that phosphorus fertilizer application significantly affects yield and yield components of bread wheat. Similarly, phosphorous fertilizer application at different rates increased grain yield of bread wheat by 28 to 44% compared to the control. Furthermore, the study was revealed that phosphorus critical (Pc) point for bread wheat was 19, and phosphorus requirement factor was also 3.30. Therefore, future research should focus on verification of the result on farmland before disseminating the technology to the end-user.