Abstract

Mulugeta Eshetu*, Regassa Gosa, Tesfaye Ketema, Girma Getachew

Nitrogen and phosphorus fertilizers are the major limiting factors for crop production in soils of the study area. In previous years’ soil test-based phosphorus calibration studies were conducted in the Sinana district, and 46 N kg ha-1, P critical (4.60 ppm), and P requirement factor (20 ppm) were recommended for food barely production. In this study, an on-farm field experiment was conducted to verify the Phosphorus Critical (Pc) level and Phosphorus requirement factor (pf) determined during soil test crop response based phosphorus fertilizer calibration study for food barely production in 2022 bona (July to December) main cropping season. The treatments and experimental setup included (1) Control (without fertilizer), (2) Blanket recommendation (farmer practices), and (3) Soil test crop response-based phosphorus recommendation results. Improved food barely Adoshe variety used as test crop on 10 m ???? 10 m plot sizes at seven sites using farmers as replicates. Soil samples before planting were taken at 0–20 cm soil depth using random sampling and analyzed using standard laboratory procedures. Agronomic parameters of food barely were collected and analyzed using R software version 4. 1.1 software. The results show soil sample analysis varied from 6. 03 to 6.25, 1.68 to 2.62%, and ranged from 1.01 to 3.30 mg/kg for soil pH (pH-H2O), OM, and available phosphorus, respectively. The statistical analysis shows a significant (p ≤ 0.05) difference among yield and yield components of food barely. As a result, the highest grain yield (5682.43 kgha-1) with an acceptable marginal yield rate of return (4131.16%) was obtained from soil test crop response-based phosphorus recommendation results. Therefore, from this study, the Pc (4.60 ppm) and pf (20 ppm) with optimum N (46 kgha-1) were verified for food barely production in Sinana District. Further demonstration and scale-up of soil test-based fertilizer recommendation, extrapolation Pc and Pf for similar soil types as well as determining the adjusted NPS fertilizer rate based on calibrated phosphorus for food barely production should be recommended.