Soil Test Crop Response Based Phosphorus Calibration Study on Food Barley (Hordium Vulgare L.) in Degem District of North Shewa Zone, Oromia, Ethiopia

Abstract

Soil productivity decline due to different factors. Blanket recommendation of fertilizer application without considering soil types and agro-ecological of the area are among the problem to obtain sustainable production. This force to site specific nutrients managements and soil test-based crop response fertilizer recommendations. The objective of the experiment was to determine economically optimum Nitrogen, Phosphorus critical (Pc) and Phosphorus requirement factor (Prf) for food barely production in Degam district. In the first year, a field experiment were conducted using, factorial combination of four N rates (0, 46, 92 , and 138 kg ha^1-)  and five P rates (0, 10, 20 ,30 and 40) were applied  to determine optimum N, the treatment laid out in randomized complete block design with three replications. Food barely (HB-1307 variety) was used.  Soil sample before plating and intensive soil samples after 21 days of sowing were taken from each plot and analyzed for selected physicochemical properties. Phosphorus critical level (Pc) determination was done using C'ate-Nelson diagram method. Agronomic data such as plant height, Spike length, biomass and grain yield were collected and subjected to two-way factorial analysis of variance (ANOVA) using R software while the partial budget analysis was done using CIMMYT (1998). The results indicate that combined NP fertilizer rates significantly influenced the agronomic parameters of food barely. Optimum nitrogen rate (92 N kg/ha), P critical (5.8 ppm) and P requirement factor (14.72) for food barely production in Degam District. Therefore, areas having similar soil conditions and agro-ecology is advisable to uses these finding. Farther verification of the result on farm land could be a pre-request before publicizes the technology to the user.