水氮互作对小麦土壤硝态氮运移及水、氮利用效率的影响

Effects of irrigation and nitrogen interaction on soil NO_3^- -N transport,nitrogen use efficiency and water use efficiency in wheat

为给强筋小麦(Triticum aeativum L.)高产优质栽培的水、氮合理运筹提供理论依据,在高产地力条件下,选用强筋小麦品种济麦20,设置不施氮(N0)、施氮180 kg/hm^2(N1)、240 kg/hm^2(N2)3个施氮水平,每个施氮水平下设置不灌水(W0)、底墒水+拔节水+开花水(W1)、底墒水+冬水+拔节水+开花水(W2)、底墒水+冬水+拔节水+开花水+灌浆水(W3)4个灌水处理,每次灌水量均为60mm,研究了水氮互作对麦田耗水量、土壤硝态氮运移、氮素利用效率和水分利用效率的影响。结果表明,(1)增加施氮量,开花期和成熟期0—140 cm各土层的土壤硝态氮含量显著升高;增加灌水时期,土壤硝态氮向深层的运移加剧,成熟期0—80 cm各土层的土壤硝态氮含量降低,120—140 cm土层的土壤硝态氮含量升高。N1W1处理在开花期0—60cm土层的土壤硝态氮含量较高,成熟期土壤硝态氮向100—140 cm土层运移少,有利于植株对氮素的吸收。(2)随施氮量的增加,子粒产量先升高后降低,以N1最高。N1水平下,W1处理获得了较高的子粒产量、子粒氮素积累量、氮素利用效率、氮肥农学利用率和氮肥偏生产力;在此基础上增加冬水(W2),上述指标无显著变化;再增加灌浆水(W3),上述指标显著降低。(3)施氮提高了小麦对土壤水的利用能力,随施氮量增加,土壤供水量及其占总耗水量的比例显著升高。N1水平下,W1处理获得了最高的水分利用效率;再增加灌水时期,水分利用效率显著降低,开花至成熟阶段的耗水模系数显著升高,灌水量占总耗水量的比例升高,降水量和土壤供水量占总耗水量的比例降低。本试验条件下,施氮为180 kg/hm^2,灌底墒水+拔节水+开花水3水的N1W1处理,是兼顾高产、高效的水氮运筹模式。

To provide theoretical basis for the culture of strong gluten wheat （Triticum aeativum L.）, the effects of irrigation and nitrogen interaction on water consumption, soil NO3-–N transport, nitrogen use efficiency and water use efficiency were studied using winter wheat cultivar Jimai 20 which had high grain yield and high process quality. Three nitrogen fertilization levels （ N 0 kg/ha （N0）, N 180 kg /ha （N1） and N 240 （N1） kg/ha）, and four irrigation treatments W0 （no irrigation）, W1 （irrigation before sowing, at jointing and at anthesis stage）, W2 （irrigation before sowing, before winter, at jointing stage and at anthesis） and W3 （irrigation before sowing, before winter, at jointing stage, at anthesis and during grain filling）, with 60 mm water each time） were adapted. The results were as follows. （1）Soil NO3-–N content in 0–140 cm soil layers at anthesis and maturity was increased with the increase of N fertilizer rate. At the same N fertilizer rate, increasing irrigation rate reduced soil NO3-–N content in 0–80 cm soil layers and increased that in 120–140 cm soil layers at maturity. The treatment N1W1 promoted wheat plant uptake N and resulted in a reasonable soil NO3-–N content within 0–80cm soil layer and 100–140 cm soil layer respectively, at maturity. （2） With the increasing of N fertilizer, the grain yield increased first then decreased. Treatment N1 had the highest grain yield in the end. Under the N level of N1, W1 had higher grain yield, higher grain N absorption, higher N use efficiency, higher agronomic efficiency of N fertilizer and higher N partial factor productivity. However, no significant differences between these index were found under W2 level, （3） Nitrogen application promoted the utilization of soil water. With the increase of N fertilizer rate, the soil water consumption and the ratio of it to total water consumption significantly increased. Under the N1 level, W1 had the highest water use efficiency （WUE）. Additional water supply reduced WUE significantly and enhanced water consumption index from the blooming stage to maturity. Under the experiment station, the treatment N1W1 （ N 180 kg per ha and 3 times irrigation （before sowing, at jointing stage and at anthesis） was recommended due to its high grain yield, high process quality and high NUE and WUE.