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

Abstract

Background: 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. Results: 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. Conclusion: 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.

Evaluation of different levels of nitrogen, zinc and their combined effect on yield and yield contributing traits of wheat

“…Prodip. Previous studies showed that the application of 150 kg/ha N resulted in increased plant height, spike length, number of spikelets per spike, weight of grains per spike, 1000 grain weight, grain yield and biological yield (Mandic et al, 2015;Adnan et al, 2016, Belete et al, 2018, which is in accordance with present findings. Research reported that higher grain yield (8.0 t/ha) was gained with the treatment receiving 240 kg N/ha than in control (3.9 kg/ha), 120 kg N/ha (4.4 t/ha), and 360 kg N/ha (6.5 t/ha) (Abedi et al, 2011), while grain yield was 5.81 t/ha due to the supplement of 160 kg N/ha in the present study.…”

“…Nitrogen is the key nutrient element and plays an inevitable role to increase the tillering capacity which leads to higher yield potential. Optimum supply of nitrogen raises the nutritive value, protein content and improves the baking quality of wheat (Ames et al, 2003;Mandic et al, 2015).Application of nitrogen has considered as a primary means of increasing wheat grain yield as well as improves N uptake and N use efficiency and consequently nitrogen harvest index (Belete et al, 2018). Zinc (Zn) is an important metal component which is the functional, structural and regulatory cofactor of a large number of enzymes (Cakmak, 2008) and essential micronutrient which deficiency is common in wheat growing areas of Bangladesh, particularly in calcareous areas with high soil pH (Majd et al, 2015).Zinc deficiency severely reduces wheat production and nutritional quality of grains (Firdous et al, 2018).The functional role of Zn includes auxins metabolism, nitrogen metabolism and protection of cells against oxidative stress.…”

Seeding rate and nitrogen fertilizer rate effect on dryland no‐till hard red spring wheat yield and quality

“…At Teton, NUE values were significantly affected by N fertilizer rate, and a stepwise decrease in NUE was noted as N rates increased. Belete, Dechassa, Molla, and Tana (2018) and Haile, Nigussie, and Ayana (2012) reported a decreasing trend in NUE with increasing N rates. At the Pondera site, although NUE was numerically higher for plots fertilized with the lowest N rate (28 kg N ha −1 , planted at the 67 kg ha −1 PLS seeding rate), overall, NUE values were comparable across applied N rates and the differences were not statistically significant ( Figure 6).…”

Biochar addition coupled with nitrogen fertilization impacts on soil quality, crop productivity, and nitrogen uptake under double‐cropping system

“…In this regard, the biochar amendment is a viable strategy together with N fertilization. N application is key for increasing crop yields and biomass production (Ali, Khan, Imran, et al, 2019;Ali, Khan, Munsif, et al, 2019;Belete, Dechassa, Molla, & Tana, 2018;Lee, Wycislo, Guo, Lee, & Voigt, 2017).…”