Effect of Nitrogen Fertilizer and Seed rates on Yield and Yield Components of Bread Wheat in the Irrigated Condition of South West Shewa, Central Highland of Ethiopia

Abstract

Inappropriate seed density and fertilizer management can lead to unstable crop yields. Excessive fertilizer application can potentially cause yield loss and nitrogen (N) leaching that leads to environmental pollution. The aim of this study was to explore the optimal N application rate and seed rate on bread wheat with different nitrogen responding under irrigation condition at two experimental sites in the South West Shewa, Ethiopia. A year field experiment was conducted to explore the effects of five N application rates (N0, N23, N46, N69, and N92) and three seed rates on bread wheat yield components like; - aboveground biomass, harvest index, number of tillers per plant, spike length, number of kernels per plant, grain yield and net return. The results showed that N application rate and seed rate were significantly interaction (P< 0.05) effect on aboveground biomass, harvest index, number of tillers per plant, spike length, number of kernels per plant and grain yield. Generally, spike length, number of tillers per plant and number of kernels per spike of wheat were increased with increased at some level in nitrogen fertilizer rate for the three seed rate at both locations. Highest number of kernels per spike (42.00, 44.00) and the highest mean above ground biomass yield (13.70 t ha<sup>-1</sup>, 7.5 t ha<sup>-1</sup>) were obtained for 150 kg ha <sup>-1</sup> seed rate with 69 N kg ha<sup>-1</sup> application at Ameya and Woliso sites respectively. The highest net benefit of 171531.88 EB ha<sup>-1</sup> with marginal rate of return of 351.14% was obtained from 175 kg ha<sup>-1</sup> seed rate with application of 69 kg N ha<sup>-1</sup>. Therefore, 175 kg ha<sup>-1</sup> seed rate with application of 69 kg N ha<sup>-1</sup> is economical feasible for bread wheat production at Ameya area and also the highest net benefit of 51675 EB ha<sup>-1</sup> with marginal rate of return of 115.22% was obtained from 150 kg ha <sup>-1</sup> seed rate with application of 69 kg N ha<sup>-1</sup> at Woliso area.