不同施氮量下灌水量对小麦耗水特性和氮素分配的影响

Effect of irrigation regimes on water consumption characteristics and nitrogen distribution in wheat at different nitrogen applications

研究了不同施氮量条件下灌水量对高产小麦耗水特性和氮素分配利用的影响。设置4个施氮水平:0kg·hm-2(N0)、120kg·hm-2(N1)、210kg·hm-2(N2)和300kg·hm-2(N3),在每个施氮水平下设置4个灌水量处理:不浇水(W0)、底墒水+拔节水(W1)、底墒水+拔节水+开花水(W2)、底墒水+拔节水+开花水+灌浆水(W3),每次灌水量60mm。结果表明:(1)在N0水平下W0处理日耗水量以拔节至开花期最高,在N1水平下,拔节至开花期日耗水量与开花至成熟期的无显著差异。同一施氮水平下,小麦开花后总耗水量、耗水模系数和日耗水量随灌水量的增加而提高,但产量随灌水量的增加先升高后降低。(2)同一施氮水平下,成熟期W1处理20—140cm各土层土壤含水量低于W2和W3处理,140—200cm土层土壤含水量与W2处理无显著差异;W1处理0—40cm土层土壤硝态氮含量及植株氮素在籽粒中的分配比例高于W2和W3处理,100—140cm土层土壤硝态氮含量及植株氮素在营养器官中的分配量和分配比例低于W2和W3处理。表明灌溉底墒水和拔节水的W1处理,促进了小麦对20—140cm土层土壤水的吸收利用,减少了土壤硝态氮向100cm以下土层的淋溶,而且有利于营养器官中氮素向籽粒的再分配,水分和氮素利用效率较高。(3)在试验条件下,施纯氮210kg·hm-2、灌溉底墒水和拔节水的N2W1处理,籽粒产量最高,水分利用效率和氮素利用效率较高,可供生产中参考。

The irrigation effects on water consumption characteristics and nitrogen distribution and utilization in wheat plants at different nitrogen application rates in the high-yielding conditions were studied.Four treatments of nitrogen levels were set：0 kg hm^-2（N0）,120 kg·hm^-2（N1）,210 kg·hm^-2（N2）,and 300 kg·hm^-2（N3）;and four irrigation rates were set under each nitrogen level：no water（represented as W0）,basal ＋ jointing water（W1）,basal ＋ jointing ＋ anthesis water（W2）,basal ＋ jointing ＋ anthesis ＋ filling stage water（W3）,at 60mm every time.The results show that：（1） On W0 conditions,the water consumption amount（WCA） per day of N0 treatment during the period from jointing to anthesis was higher than those during other periods,the WCA per day of N1 treatment during the period from jointing to anthesis had no significant difference from those during the period from anthesis to maturity.At the same nitrogen application rate,the total WCA,module index,WCA per day after anthesis and the yield were increased as the irrigation rate increased,but the yield was decreased as more water was irrigated at the middle of filling stage.（2） At the samenitrogen application rate,soil water content in 20—140 cm soil layer of W1 treatment at maturity was lower than those of W2 and W3 treatments,but that in 140—200 cm had no significant difference from that of the W2 treatment.Soil NO3-N content in 0—40cm soil layer of W1 treatment at maturity was higher than those of W2 and W3 treatments,whereas that in100—140 cm soil layer was lower than those of W2 and W3 treatments;the amount and the percentage of nitrogen distributed in vegetative organs of W1 were lower than those of W2 and W3,but those distributed in kernels were higher relative to W2 and W3.It was showed that irrigation at pre-sowing and jointing promoted the absorption and utilization of water from 20-140cm soil layer,reduced soil nitrate leaching below 100 cm soil layer,and increased the nitrogen redistributed from vegetative organs to kernels,water/nitrogen-use efficiencies.（3） In the experiment,with irrigation at pre-sowing and jointing and nitrogen application at 210 kg·hm^-2 rate,the highest yield and greater water/nitrogen-use efficiencies would be achieved.