标题：Effect of nitrogen fertilizer rates on grain yield and nitrogen uptake and use efficiency of bread wheat ( Triticum aestivum L.) varieties on the Vertisols of central highlands of Ethiopia
摘要：Nitrogen is one of the most important nutrients limiting yield of bread wheat in Ethiopian highlands. Application of a large amount of N fertilizer has been a method of increasing yield in the study area which is costly and can cause environmental pollution. Therefore, a field experiment was conducted for two consecutive years (2014 and 2015) to evaluate the effect of N application rates on grain yield, nitrogen uptake and N use efficiency of bread wheat varieties. The treatments consisted of a factorial combination of four rates of nitrogen (0, 120, 240 and 360 kg ha−1) and three popular wheat varieties (Menze, Tsehay and ET-13) in a randomized complete block design with four replications. The two-way interaction of year and N rate, N rate and variety significantly affected grain nitrogen concentration. The interaction of year and variety and N rate and variety affected grain and straw nitrogen concentrations, respectively. The three-way interaction of year, N fertilizer rate and variety significantly affected (P < 0.01) grain yield, grain and total nitrogen uptake, agronomic efficiency, agro-physiological efficiency and apparent recovery efficiency. The highest grain yield (5718.32 kg ha−1) was obtained from variety Menze at N rate of 360 kg ha−1 in 2015 which was statistically at par with the application of 240 kg N ha−1 and with variety Tsehay at N rate of 240 and 360 kg N ha−1 during the same growing season. The highest grain and straw (2.7 and 0.35%, respectively) nitrogen concentration were produced by variety Tsehay at N rate of 360 kg ha−1. The highest apparent nitrogen recovery efficiency was recorded for variety Tsehay at N rate of 120 kg ha−1 in both growing seasons. Hence, it could be concluded that varieties Menze and Tsehay produced the highest grain yield followed by variety ET-13. All wheat varieties tested did not show a significant variation in most of the nitrogen use efficiency parameters, and these efficiency parameters decreased with the increasing rate of N beyond 120 kg ha−1 in both growing seasons.
Loading...
