氮肥对节水栽培冬小麦产量、土壤硝态氮残留的影响

Effect of N Application on Grain Yield of Winter Wheat and Accumulation of NO_3^--N Under Water-Saving Cultivation System

在节水栽培条件下,研究了不同施氮量及氮肥运筹对冬小麦产量、氮肥利用率及生育期间土壤硝态氮的时空变化特征,同时计算了成熟期土壤硝态氮残留量。结果表明,节水栽培条件下冬小麦产量对氮肥反应不明显,氮肥利用率则随施氮量增加而显著降低,同时氮肥用量的增加显著增加了成熟期土壤硝态氮残留量。不同生育期0~60 cm土层硝态氮含量均随施氮量增加而增加,开花期表现为施氮量157.5 kg/hm2或226.5 kg/hm2时氮肥一次性底施处理硝态氮含量均低于分次施用处理,成熟期表现为施氮量157.5 kg/hm2时氮肥分次施用处理高于一次性底施处理,而施氮量226.5 kg/hm2则相反。由此可见,节水栽培条件下施氮量157.5 kg/hm2一次性底施既可满足冬小麦高产的要求,同时土壤硝态氮残留量较低。

A field experiment was carried out in order to identify the effect of rates and method of nitrogen application on grain yield of winter wheat, fertilizer nitrogen use efficiency, and accumulation of NO3^--N, under water-saving cultivation system. The experiment was conducted at the Wuqiao Experiment Station of China Agricul- ture University, Cangzhou city, Hebei province. The experiment was designed as a random spot with three replications with the cultivar Shijiazhuang 8 No. The treatment were six nitrogen rate and method （0, 157.5 ＋0, 88.5＋69, 157.5＋69, 123＋103.5, 226.5＋0 and 157＋138.5 N kg/hm^2）. The nitrogen fertilizer was applied before sowing and at jointing, respectively. The results showed that the grain yield of winter wheat, which ranged from 7 618 to 8 063 kg/hm2, did not respond to nitrogen fertilizer in water-saving cultivation system. The water use efficiency ranged from 1.72 to 1.86 kg/m^3 But the nitrogen use efficiency significantly increase at 0.05 level with the rates of nitrogen application. However, at the same time, the amounts of soil NO3^-- N residue at harvest significantly increase with the rates of nitrogen application also. The soil NO3^--N content in 0 60 cm increase with the rates of nitrogen application at jointing, anthesis and harvest, respectively. The soil NO3^--N content of two split application was higher than that of basal application when the nitrogen fertilizer rates was 157.5 kg/hm^2 at anthesis and harvest, respectively. Although, the soil NO3^--N content of two split application was higher than that of basal application when the nitrogen fertilizer rates was 226.5 kg/hm^2 at anthesis, and results were opposite at harvest. The results suggested that under water-saving cultivation system winter wheat can achieve high grain yields, while lower soil NO3^--N content with basal application at the level of 157.5 kg/hm^2 nitrogen fertilizer.