雨养和灌溉条件下施氮量对小麦干物质积累和产量的影响

为给冀东地区小麦高产栽培提供技术参考,以高蛋白质品种京冬8号和低蛋白质品种宝麦38为材料,设置0、120、240和360kg·hm-2三个施氮水平,研究了在灌溉和雨养条件下氮素营养对冬小麦干物质积累和产量形成的调控效应。结果表明,适量施氮提高了小麦干物质积累量、结实小穗数和穗粒数,促进了叶片、茎和鞘的花前贮存干物质在花后向籽粒中的转移,但过量施氮则抑制灌溉条件下营养器官花前贮存干物质在花后向籽粒的转移。施氮量对千粒重的影响因基因型和土壤水分状况不同而差异。随施氮量的增加,在雨养和灌溉条件下京冬8号千粒重分别呈降低和增加趋势,宝麦38千粒重均呈下降趋势。适当施氮可促进分蘖和分蘖成穗。与雨养栽培相比,灌溉可促进小麦干物质积累,增加穗数和延长灌浆时间,提高籽粒产量。随着施氮量的增加,两品种的氮肥生产效率和氮肥农学效率均降低。宝麦38和京冬8号籽粒产量达到最高的施氮量在雨养条件下均为120kg·hm-2,在灌溉条件下分别为120和240kg·hm-2。从产量和氮肥利用效率综合来看,宝麦38的适宜施氮量为120kg·hm-2,京冬8号的适宜施氮量为120~240kg·hm-2。

Effects of Nitrogen Application Rate on Dry Matter Accumulation and Grain Yield of Winter Wheat under Irrigated and Rainfed Conditions

High protein variety Jingdong 8 and low protein variety Baomai 38 was used to investigate the effect of nitrogen (N) rate on dry matter accumulation and yield formation of wheat under irrigated and rainfed conditions. The results showed that with the proper increase of N rate, the amounts of accumulation and translocation of dry matter in the leaves, stems and sheathe increased, and the number of grain and spikelet of the two cultivars increased, but the translocation of dry matter accumulated before flowering was reduced while high N rate under irrigated condition. The effects of N application on the 1 000 grain weight varied with wheat genotypes and soil moister contents. With the increase of N application rate, the 1 000 grain weight of Jingdong 8 decreased under rainfed condition and increased under irrigated condition, while that of Baomai 38 decreased under both conditions. Increasing N rate properly might promote tillering and improve ratio of spikes to tillers. Compared with that under rainfed condition, plant dry matter accumulation was increased, the total number of spikes at mature stage was improved, and the duration of grain filling was prolonged under irrigated condition, which resulted in a higher grain yield. The highest yield was obtained for both cultivars at N rate of 120 kg·hm^-2 under rainfed conditions, and it was obtained at N rate of 120 kg·hm^-2 for Baomai 38 and at 240 kg·hm^-2 for Jingdong JP2]8 under irrigated conditions. Under the test conditions, the appropriate N amount for Baomai 38 was 120 kg·hm^-2 , but that for Jingdong 8 was 120~240 kg·hm^-2.JP]