Effect of NPS and Urea Fertilizer Rates on Phenology, Growth and Yield Components of Bread Wheat (Triticum Aestivum L.) in West Guji Southern Oromia

Abstract

Bread wheat ( Triticum aestivum L.) is one of the major food crops cultivated in West Guji and plays a significant role in ensuring food security in Ethiopia. However, low soil fertility and inadequate fertilizer application are among the major constraints limiting wheat productivity in the study area. The study took place in the West Guji southern Oromia, during the main cropping season in 2023. The study was aimed to determine the combined application of NPS and urea (N) fertilizer rates for bread wheat (Triticum aestivum L.) production. The treatments were (0 NPS) negative control, 60 kg NPS, 120 kg NPS, and 180 kg NPS, and (0 N) negative control, 140 kg N, 280 kg N, and positive control (100/100 kg ha⁻ 1 NPS/N). The treatments were arranged in a randomized complete block design and replicated three times. The results of the analysis of variance for agronomic characters indicated that the effects of fertilizer application rates were significant for the date of 50% heading, the date of 90% physiological maturity, plant height, the number of total tillers per plant, spike length per plant, effective tiller per plant, spikelet per spike, the number of grains per spike, thousand seed weight, and harvest index. The maximum duration of 50% days to heading (83.67 days) and day to 90% physiological maturity (136 days) was obtained from unfertilized plants, whereas the minimum duration of 50% day to heading (70.33 days) and day to 90% physiological maturity (120 days) was obtained from 180 kg NPS ha⁻ 1 + 280 kg N ha⁻ 1 fertilizer rates, respectively. The maximum plant height (92.5 cm) was also recorded under the highest fertilizer treatment, indicating a strong correlation between nutrient application and plant growth. These findings suggest that balanced fertilizer rates can significantly enhance both yield components and overall plant development. 21 cm), effective tiller per plant (5.21), number of total tillers per plant (5.25), spike length (9.21 cm), and 180 kg NPS ha⁻ 1 + 280 kg N ha⁻ 1 fertilizer rates, respectively. The maximum spikelet per spike (19) and number of grains per spike (74.67) were obtained from 120 kg NPS ha⁻ 1 + 140 kg N ha⁻ 1 fertilizer rates, respectively. The maximum thousand grains weight (38.00 gm) and harvest index (44.33%) were obtained from 180 kg NPS ha⁻ 1 + 140 kg N ha⁻ 1 fertilizer rates, respectively. Therefore, 180 kg/280 kg and 180 kg/140 kg ha⁻ 1 NPS/urea (N) are better, but 120/140 kg is best for gain yield, and the farming community can be used in the study area. This suggests that optimizing fertilizer application can significantly enhance bread wheat yield and yield components. Future research should focus on refining these rates further to maximize efficiency and sustainability in agricultural practices.