Effects of nitrogen fertilizer rates and ratios of base and topdressingfertilizer on yield, quality  of tobacco leaves and N-use efficiency

The most popular tobacco cultivar, Zhongyan 100, in Henan province was used to study the effects of different application measures of nitrogen (N) on yield of fluecured tobacco, N use efficiency and nitrogenous compounds of tobacco leaves. The results show that compared with the control treatment (without nitrogen), the yields of tobacco leaves, nitrogenous compounds and N use efficiencies are significantly increased under the N application treatments, and the yields and the production values are increased by 10.0%-56.7% and 11.6%-43.1%, respectively. Under the same amount of nitrogen application, with the increase of topdressed nitrogen rate, the yields, nitrogenous compounds and N use efficiency of tobacco are increased. At the N application level of 37.5 kg/ha, the production value is increased with the ratio of topdressed N to basal N fertilizer increasing. The treatment of 75% basal N and 25% topdressed N has the highest production values under both 60 kg/ha N application level and 82.5 kg/ha N application level. At the same ratio of basal N to topdressed N fertilizer, the partial factor productivity of the applied N is decreased with the nitrogen application increasing, and the N use efficiency and the production value are the highest under the N 60 kg/ha level. Based on the comprehensive analysis of the yields of tobacco leaves, appropriate nitrogenous compounds, increases of the production value and the N use efficiency, the treatment with the best effect is the amount of nitrogen application at 60.0 kg/ha and the proportion of basal N application at 50%-75%.