EFFECTS OF BLENDED NPSB FERTILIZER RATES ON SELECTED SOIL PROPERTIES, YIELD AND YIELD COMPONENTS OF MAIZE (Zea mays L.) AT BANSHURE KEBELE IN BEDELE DISTRICT, SOUTH WESTERN ETHIOPIA

Soil test based fertilizer recommendation concurrent to the actual limiting nutrients for a given crop helps to supply adequate and balanced plant nutrients for sustainable crop production without affecting soil health negatively. Blended NPSB fertilizer is a newly introduced fertilizer for crop production in the study area. However their optimum rate for maize crop production and their impact on selected soil property is not yet determined in the study area. Therefore a study was conducted to investigate the effects of blended NPSB fertilizer rates on selected soil properties, maize yield and yield components in Bedele district at Banshure Kebele during the 2021main cropping season. The experiment was laid out in randomized complete block design (RCBD) with three replication of the treatments (0, 25, 50, 75, 100, 150, 200, 250 and 300 kg ha 1 ) of blended NPSB fertilizer rates supplemented with the recommended nitrogen rate for maize production in Bedele District. Selected soil properties before and after trial were analyzed following standard laboratory procedure at soil laboratory of Bedele Agricultural Research Center. Soil analytical results before planting indicated that, the soils of the research sites had clay textural class, are moderately acidic (5.48 and 5.47), medium in OC content (2.04 and 2.12%), had low TN (0.17 and 0.18%), medium available P (1.67 and 1.77 mg kg-1 ), low available S (9.26 mg kg-1 ), low available B (0.3 and 0.36 mg kg-1 ), medium CEC (20.94 and 22.64 cmol (+) kg-1 ) and very low PBS (16.85 and 16.29%), for Alle and Abu respectively. The analysis of variance indicated that, the blended NPSB fertilizer rate highly significantly affected soil pH, available phosphorus, available boron, available sulfur, maize growth, yield and yield components. Moreover, the result showed that economically feasible grain yield (7173.6 kg ha-1 ) and net benefit (74897.58 ETB ha-1 ) with highest marginal rate of return of 2957% were obtained from the plot treated with 150 kg ha-1 of blended NPSB fertilizer rate. Therefore, based on the result obtained from this study, application of 150 kg ha-1 of blended NPSB fertilizer rate and recommended nitrogen can be tentatively suggested as economically profitable for the production of maize at the study area.