EFFECTS OF NPSB RATE ON SELECTED SOIL CHEMICAL PROPERTIES AND BREAD WHEAT (Triticum aestivum L.) YIELD AT BOYENA TUPA IN CHENCHA DISTRICT, SOUTHERN ETHIOPIA

Wheat is one of the most important cereal crops produced in Ethiopia. However, its production is low mainly due to low soil fertility and poor soil fertility management practices. Field experiment was conducted during 2019 cropping season in Chencha district, Southern Ethiopia to determine the effect of NPSB rates on wheat yield and yield parameters and assessing the effect of the aforementioned fertilizer on selected soil properties. Treatments used for the field experiment were; (1) Control, (2) 50, (3) 75, (4) 100, (5) 125, (6)150, (7) 175 and (8)200 kg NPSB ha,-1 and 100 kg urea ha-1 was applied to all treatments. The experiment was laid out in RCBD with three replications. The wheat variety used was Hidassie. Soil samples were collected from the experimental field before commencement of the experiment and from each plot after wheat harvesting. The soil samples were analyzed for selected physical and chemical properties following standard methods. Soil analysis results before sowing revealed that soil textural class was clay loam, pH 5.82, bulk density 1.22 g/cm3, exchangeable acidity 0.72 meq/100 g, CEC 24.40 meq/100 g, organic carbon 1.63%, total N 0.074%, available phosphorus 9.5 ppm, available sulfur 15.52 ppm, available boron 0.1 ppm and PBS 48.10%. Applications of different rates of NPSB blended fertilizer significantly affected yield and yield components of wheat, and soil physicochemical properties. The highest plant height (73.60 cm), spike length (7.06 cm), tiller number (6.26), biomass (7,604 kg ha-1), grain yield (5,375 kg ha-1) and thousand seed weight (79.00 g) were recorded from application of 200 NPSB kg ha-1 + 100 kg urea ha-1. The lowest above ground dry biomass (4,854 kg ha-1), grain yield (2,646 kg ha-1), plant height (55.87 cm), spike length (4.60 cm), total tiller number (1.33) and thousand seed weight (63.00 g) were recorded on the control plot. Application of 50 kg NPSB ha-1 + 100 kg urea ha-1 gave economically feasible grain yield. The highest net return (22,520.39 ETB ha-1) with (MRR %) 34.99 was obtained from the same treatment plot. This experiment indicates that application of NPSB blended fertilizer can increase the grain yield of wheat. But the experiment was only one season and single location, for further recommendation, additional studies across locations and on different soil types will be needed.