Journal of Agricultural Science and Practice

The study was conducted for two years on farmers’ fields in Nagelle Arsi District in 2018/19 to 2019/20 to evaluate the effect of rates of NPS fertilizer on growth, yield and yield components of bread wheat and to determine economically appropriate rate of NPS fertilizer for bread wheat production. The experiments were laid out in randomized complete block design (RCBD) with two replications with a plot size of 5 m x 4 m accommodating 20 rows each spaced 20 cm. Spacing of 1.0 m and 0.5 m were maintained in between adjacent blocks and plots, respectively. The treatments consist of 100% Pc from TSP fertilizer and 100, 75, 50, 25% Pc from NPS fertilizer and control (no fertilizer application) on a bread wheat variety Ogolcho with seed rate of 150 kg ha^-1. Weed and yellow rest were managed by pallas and rexcido, respectively. The effects of NPS fertilizer rate on mollic andosols was highly significant with phosphorus critical and requirement factors (p<0.01) on plant height, aboveground dry biomass and grain yield whereas spike length, seed per spike and thousand kernels weight were not significant. Also, the effects of NPS fertilizer rate on eutric vertisols was highly significant with phosphorus critical and requirement factors (p<0.01) on spike length, seed per spike, aboveground dry biomass and grain yield whereas the plant height and thousand kernels weight were not significant. The highest grain yield was obtained in 100% pc TSP with recommended rate of 46 kg N ha^-1 followed 100% pc NPS with recommended rate of 46 kg N ha^-1. The lowest yield (2468 kg ha^-1) was obtained in control. The partial budget analysis showed that the maximum net benefit with an acceptable marginal rate of return (MRR) was obtained from 75% pc NPS fertilizer and supplemented rate of 69 kg N ha^-1 application on eutric vertisols and 100 % pc NPS fertilizer and supplemented rate of 46 kg N ha^-1 application on mollic andosols.