氮肥管理对高寒地区冬小麦氮素积累的影响

Effect of nitrogen management on nitrogen uptake of winter wheat in cold area

采用田间小区试验方法,测定0~90 cm土层土壤无机氮、叶片叶绿素值、干物质积累、氮积累和小麦产量,研究氮肥管理对冬小麦产量和氮效率影响。结果表明,习惯施肥,大量氮肥施用在返青期,增加拔节期和抽穗期叶片SPAD值,促进拔节期前干物质积累和抽穗前氮素积累,抑制抽穗期后干物质和氮素积累,造成0~60 cm土层无机氮较高残留;通过氮肥优化管理可防止土层无机氮含量过高,促进抽穗后干物质和氮素积累增加;在氮肥用量降低42.8%~47.6%条件下,冬小麦产量提高4.2%~13.1%,氮肥偏生产力提高95.5%~98.7%（P〈0.05）。

Field experiment was conducted to study the effect of nitrogen management on wheat yield and nitrogen use efficiency. Inorganic nitrogen （Nmin） of 0-90 cm soil layer, and soil and plant analysis development section （SPAD） value, accumulation of dry matter, nitrogen uptake, wheat yield were measured. The experiment results showed that farmer＇s fertilization practice, applying excessive nitrogen fertilizer at turning green period, increased SPAD value of leaves at jointing and heading stage, enhanced the dry matter weight before jointing stage and nitrogen uptake before heading stage, but inhibited the dry matter and nitrogen accumulation after heading stage and increased residual Nmin in 0-60 cm soil layer. Optimized nitrogen management （OPT） can match wheat nitrogen demand by applying nitrogen at jointing so that 0-60 cm soil layer Nmin maintained appropriate level and improved dry matter weight and nitrogen uptake after heading. The nitrogen rate of OPT was decreased by 42.8%-47.6% compared to farmer＇s fertilization practice, but the wheat yield was improved by 4.2%-13.1% and partial factor productivity of nitrogen fertilizer was enhanced by 95.5%-98.7% （P〈0.05）.