Effects of Blended NPSB Fertilizer Rates on Growth, Yield and Yield Components of Bread Wheat (Triticum aestivum L.) Varieties on Jimma Arjo District, Western Ethiopia

Wheat (Triticum aestivum L.) is one of the most important cereal crops in Ethiopia, however the yield of the crop is low mainly due to low soil fertility management, lack of using balanced fertilizer and lack of using improved wheat varieties. The experiment was conducted to determine the effect of varieties, fertilizer rate and their interaction on yield and yield components and to determine the economic feasibility of application of fertilizer for optimum yield of bread wheat varieties. The experiment was conducted in Jimma Arjo district with four levels of NPSB fertilizer rates (0, 50, 100, 150, and 200 kg ha-1) and 64/20 NP and three bread wheat varieties (Ogolcho, Huluka and Hidase) combined factorially and laid out in a Randomized Complete Block Design with three replications. The soils of the experimental area exhibited high sand (36%) but relatively low clay fractions (30%). Before sowing, the soils of the experimental site showed mean soil pH (H2O) value of 5.52, organic carbon content of 2.21%, total N (0.19%) available P (10.02%), organic matter content (3.80%), and available boron of 0.99 ppm.. The main effect of varieties and NPSB fertilizer application were significant for all parameters of bread wheat varieties except harvest index and only seed per spike and thousand seed weight were significant for interaction. The highest mean grain yield of 5801 kg ha-1 was obtained for Huluka bread wheat variety with applications of 150 kg NPSB ha-1 and 200 kg urea ha-1 fertilizers. The lowest 1599 kg ha-1grain yield was recorded from Hidase with no fertilizer. The highest net benefit ETB 154288 ha-1 with marginal rate of return of 3210% and value to cost ratio of ETB 66.19 per unit of investment for bread wheat production was obtained from application of 150 kg NPSB ha-1 and 200 kg Urea ha-1. In conclusion, application of 150 kg ha-1 NPSB enhanced bread wheat yield and, therefore, recommended for bread wheat production.