EFFECT OF SEED AND BLENDED FERTILIZER (NPS) RATES ON YIELD AND YIELD COMPONENTS OF BREAD WHEAT (Triticum aestivum L.) IN EAST BADAWACHO DISTRICT, SOUTHERN ETHIOPIA

Low soil fertility and poor crop management practices including use of inappropriate seeds rates are among the major constraints limiting the productivity of wheat in Ethiopia in general and in the study area in particular. Thus, field experiment was conducted to assess the effect of rates of seed and blended fertilizer (NPS) on growth, yield components and yield of bread wheat and to identify economicaly feasible rates of seed and blended NPS in the study area. Factorial combination of three levels of wheat seed rates (100, 125 and 150 kg ha-1), five levels of NPS (0, 50,100, 150, 200 kg ha-1) fertilizer, currently recommended 100 kg of DAP (18 kg N and 46 kg P2O5 ha-1) and 100 kg of urea (46 kg N ha-1) were used. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. The results revealed that the spike length, number of kernels per spike, total dry biomass yield and harvest index were significantly (P < 0.01 ) affected by the main effects of NPS and seed rate. The maximum spike length (7.77 cm), number of kernels per spike (61.5), total dry biomass yield (12303 kg ha-1) were obtained at the NPS rate of 200 kg ha-,1 while the highest harvest index (0.42) was recorded at NPS rate of 150 kg ha-1. Similarly, the maximum spike length (7.72 cm) and number of kernels per spike (56.85) were recorded at seed rate of 100 kg ha-1 while the highest total dry biomass yield (11568 kg ha-1) and harvest index (0.41) were recorded at seed rate of 150 kg ha-1. The interaction of the seed and fertilizer rates also significantly affected grain yield, number of total and productive tillers per m2, straw yield and lodging percent. The maximum grain yield (6250 kg ha-1), number of total tillers per m2 (466.7), number of productive tillers per m2 (413), straw yield (8646 kg ha-1) and lodging percent (38%) were recorded at combination of the highest rates i.e 200 kg NPS with 150 kg seed rate ha-1. The results obtained with the currently used 100 kg NPS with 100 kg of urea per ha-1 and blanket recommendation of DAP and urea were significantly difference in grain yield at highest seed rates i.e 150 kg seed rate ha-1. The partial budget analysis revealed that the highest net return (44378.4 Birr ha-1) with MRR 1420% was obtained from a combined applications of 150 kg NPS with seed rate of 150 kg ha-1. Based on the result of this study, it can be tentatively concluded that bread wheat at seed rate of 150 kg ha-1 and NPS rate of 150 kg ha-1 to be appropriate for bread wheat production in study area.