Response of Wheat on Uptake, Protein and Nitrogen Use Efficiency to Application of Slow Releasing Nitrogen Fertilizer in Northern Ethiopia

The N recovery by crops from the soluble N fertilizers such as urea is often as low as 30–40%, with a potentially high environmental cost associated with N losses via NH3 volatilization, NO3- leaching and N2O emission to the atmosphere. This study was initiated to evaluate the effects of slow releasing nitrogen fertilizer in nitrogen uptake, nitrogen use efficiency and grain protein content of wheat. A field experiment was carried out in 2015 main cropping season at Hawzien district in Tigray Regional State, Ethiopia. The experiment were arranged in a randomized complete block design with three replications at three farmer's field. Treatments were four levels of nitrogen (0, 32, 64 and 96) kg ha-1. The nitrogen source was UREAStabil, which is slow N releasing fertilizer. Conventional urea at recommended rate (64 kg N ha-1) was included as positive control at both sites. The highest grain and straw N uptake, and total uptake (41.81 kg ha-1, 24.28 kg ha-1, and 66.09 kg ha-1, respectively) were recorded for grain and straw harvested from plots treated with 64 kg N ha-1 in the form of UREAStabil . The highest agronomic efficiency of 9.46 kg kg-1and apparent recovery of nitrogen 55% was obtained at 64 kg N ha-1 as UREAStabil and physiological efficiency of 60.28 kg kg-1 was obtained at 64 kg N ha-1 as conventional urea. The highest and lowest grain protein content were recorded for grain harvested from plots fertilized with 96 kg N ha-1 (14.151%) in the form of UREAStabil and 0 kg N ha-1 (10.62%), respectively. It can be concluded that the highest uptake and nitrogen use efficiency was obtained on plots treated with UREAStabil than conventional urea.