氮肥对节水栽培冬小麦产量、土壤硝态氮残留的影响

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0～60cm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157．5kg／hm^2或226．5kg／hm^2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157．5kg／hm^2时氮肥分次施用处理高于一次性底施处理，而施氮量226．5kg／hm^2则相反。由此可见，节水栽培条件下施氮量157．5kg／hm^2一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。

Effect of N Application on Grain Yield of Winter Wheat and Accumulation of NO-3-N Under Water-Saving Cultivation System

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 NO_3~--N,under water-saving cultivation system.The experiment was conducted at the Wuqiao Experiment Station of China Agriculture 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/hm~2,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 NO_3~--N residue at harvest significantly increase with the rates of nitrogen application also.The soil NO_3~--N content in 0~60 cm increase with the rates of nitrogen application at jointing,anthesis and harvest,respectively.The soil NO_3~--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 NO_3~--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 NO_3~--N content with basal application at the level of 157.5 kg/hm~2 nitrogen fertilizer.