Nitrogen Use Efficiency and Maize Performance through Application of Urea Stable and Urea in Highland Nitisol of Midakegn and Toke Kutaye Districts

The field experiment was conducted in 2018 and 2019 cropping season to determine the effects of urea stable and urea on nitrogen use efficiency and maize performance in highland Nitisol of Midakegn and Toke Kutaye districts. The experiment was laid out in randomized complete block design with three replications. Nine treatments of urea stable and urea with different application times was used. Application of different nitrogen rate from urea stable and urea were significantly (P < 0.05) influenced mean plant height, leaf area index, dry biomass, grain yield, thousand seed weight and harvest index of maize crop. Significantly higher mean leaf area index (4.1), thousand seed weight (357 g), dry biomass (16472 kg ha-1) and grain yield (5475 kg ha-1) were recorded from split application of 138 kg N ha-1 from urea stable whereas higher mean plant height was recorded from split application 138 kg N ha-1 from urea. Application of nitrogen rate were also affected nitrogen uptake and agronomic nitrogen efficiency of maize. Mean agronomic nitrogen efficiency showed decreasing trend with increasing of nitrogen fertilizer application. Significantly higher and lower value of agronomic nitrogen efficiency were obtained from split application of 46 kg N ha-1 from urea stable and 138 kg N ha-1 from urea stable applied at planting. Agronomic parameters and nitrogen uptake were only influenced by nitrogen rate indicating slow releasing of nitrogen from urea stable and confirmed this form fertilizer reduce N loss. Both urea stable and urea sources of nitrogen gave similar yield at the same rates. Therefore, urea stable could be used as alternative nitrogen source in addition to urea if the cost and accessibility of this fertilizer is the same for the area.