氮肥用量对直播油菜产量及氮素吸收利用的影响

Effect of nitrogen application rate on yield and nitrogen uptake and utilization of direct seeding rape

为了明确安徽省江淮地区直播油菜氮肥的适宜用量,在安徽省江淮地区布置不同氮肥用量对直播油菜产量、氮素累积量、经济效益及氮肥利用率影响的田间试验。结果表明,施用氮肥显著提高了油菜产量和氮素累积量。施氮量高于240 kg/hm^2后,油菜籽粒产量和氮素累积量的增加趋于平缓。氮肥用量为240 kg/hm^2时获得最高经济效益10 026元/hm^2。氮肥用量为180 kg/hm^2时,油菜氮肥表观利用率达到最高(43.78%),氮肥施用量超过240 kg/hm^2,氮收获指数和肥料利用率出现下降。施氮量相同的情况下,分次施肥比起一次性施肥更有利于提高油菜产量。综合油菜的产量、肥料利用率和经济效益,安徽省江淮地区直播冬油菜施氮量在180~240 kg/hm^2能较好地协调油菜高产和氮肥合理利用的统一。

In order to clarify the appropriate amount of nitrogen fertilizer for direct seeded rapeseed in Jianghuai area of Anhui Province,field experiments were set up with different amount of nitrogen fertilizer applied to study the effects of nitrogen application on the rape yield,nitrogen accumulation,economic benefit and nitrogen use efficiency.The results showed that the yield and nitrogen accumulation of rapeseed increased significantly by the application of nitrogen fertilizer.When the amount of nitrogen application was higher than 240 kg/hm^2,the rapeseed yield and nitrogen accumulation kept the same yet.The highest economic benefit was 10026 yuan/hm^2 when the amount of nitrogen fertilizer was 240 kg/hm^2.When the nitrogen fertilizer was 180 kg/hm^2,the apparent utilization rate of rapeseed nitrogen fertilizer reached 43.78%.When the application rate of nitrogen fertilizer was higher than 240 kg/hm^2,the nitrogen harvest index and fertilizer utilization rate were both decreased.Under the same amount of nitrogen fertilizer,the rape yield,nitrogen accumulation and nitrogen utilization rate with urea applied separately were higher than that with urea applied at one time.Considering the yield,nutrient accumulation,fertilizer utilization rate and economic benefit of rapeseed,the optimal fertilizer application of direct seeded rapeseed is 180~240 kg/hm^2 in the Jianghuai region of Anhui Province.