Soil Test Crop Response Based Phosphorus Calibration Study for Bread Wheat in Shashemene District of West Arsi Zone, Oromia, Ethiopia

Abstract

Soil test based crop response phosphorous calibration study was conducted Shashemene district on bread Wheat crop during the main cropping season of 2018 -2020 with the objectives to determine Pc and Pf for bread wheat crop, and to establish site-specific soil test based phosphorus fertilizer recommendation. RCBD design was used with 3 replication using 5 rates of N (0, 46,69 and  92 kg ha-1) and 5 rates of P (0, 10, 20, 30 and 40 Kg ha-1) in a factorial combination to determine optimum level of N- rate for bread wheat crop production. In the second and third year 5 levels of P (0, 10, 20, 30, and 40 Kg ha-1) and 46 kg N ha1 of optimum nitrogen rate obtained were applied uniformly for all plots to determine P-critical value (Pc) and P-requirement factor (Pf) for bread Wheat. A total of experimental plot size 3m*3m (9 m²) and Seeds rate of 150 kg ha -1. Composite Surface soil samples from 0-20 cm depth were collected from each experimental plot before planting. Similarly, after 21 days of planting, composite soil samples were taken at (0-20 cm depth) using auger from each plot for analysis of available p using Olsen method. The result of the study showed that low to extremely high available P ranged from 7.7-56ppm. The mean maximum grain yield (5358kg/ha) was obtained from the application of 46 kg N /ha and 92 kg P2O5 /ha whereas the lowest (1873kg /ha) was obtained from control treatment. On the other hand, the combination of 69kg N/ha and 92kg P2o5/ha could result the highest net benefit of 114425.00 birr per hectare. However, 46 N kg ha-1 N fertilizers was determined as economically feasible optimum N rates at 2655%, MRR on Eutric andosol in Shashemene district for Bread wheat. From phosphorous calibration study, P-critical value (21 ppm) and P-requirement factor (4.43) was determined for phosphorus fertilizer recommendation for bread wheat crop production in the area. Therefore, the obtained result has to be verified and the economic benefit must be studied across farmers’ fields.

Keywords: Calibration, Phosphorous, Soil Test, West Arsi, Bread wheat

DOI: 10.7176/JBAH/11-10-01

Publication date:May 31^st 2021