限水减氮对豫北冬小麦产量和植株不同层次器官干物质运转的影响

采用节水栽培并减少氮肥用量是实现豫北冬小麦生产的高产、高效和环境友好发展的必然选择,探明限水减氮对冬小麦产量和植株各层次器官干物质运转的影响,可为该地区冬小麦节水栽培和合理施用氮肥提供科学依据。2009—2010和2010—2011年连续2年在河南浚县钜桥进行小麦田间裂区试验,主区设置2个灌溉水平拔节水(W1)和拔节水+开花水(W2)],副区设置5个氮肥水平330 kg hm~(–2) (N4,豫北地区小麦生产中常规施氮量)、270 kg hm~(–2) (N3)、210 kg hm~(–2) (N2)、120 kg hm~(–2) (N1)、0 kg hm~(–2) (N0)],测定了籽粒产量和植株各层次器官干物质运转量、运转率和对籽粒贡献率。减量施氮与N4相比,各营养器官向籽粒运转的干物质量均有增加,其中,穗轴+颖壳的干物质运转量增加了323.2%,增幅远高于茎节的24.5%和叶片的4.6%,且穗轴+颖壳的干物质运转率和对籽粒贡献率增幅也远高于茎节和叶片。减量施氮处理的叶片干物质运转量的增加主要源于倒三叶和倒四叶,分别增加28.7%和201.1%,而茎节干物质运转量的增加主要源于除穗位节外的其他茎节,分别增加21.7%(倒二节)、71.8%(倒三节)、44.5%(倒四节)和31.1%(余节)。与W2相比, W1干物质运转量无显著差异,但干物质运转率略高(24.6%vs. 23.8%),对籽粒贡献率较高(35.1%vs. 30.0%),籽粒产量降低11.2%,水分供应量减少750 m3 hm~(–2)。可见,减量施氮促进了营养器官,尤其是穗轴+颖壳和下层器官(倒三叶、倒四叶、倒三节、倒四节和余节)的干物质向籽粒的运转,提高了对籽粒贡献率,有利于提高籽粒产量。

Effect of lower water and nitrogen supply on grain yield and dry matter remobilization of organs in different layers of winter wheat plant in northern Henan province

Reducing irrigation and N fertilizer application is an inevitable option to meet the target of enhancing grain yield, improving nutrient use efficiency and developing friendly environment in winter wheat production of northern Henan province. Clarifying effects of lower water and nitrogen supply on grain yield and dry matter remobilization of organs in different layers of wheat plant can provide scientific basis for rational N fertilizer inputs in wheat production with limited irrigation in Northern Henan province. A field experiment was carried out at the Xun County Experimental Station, Henan province by a split-plot design with water regime as the main plot and N rate as sub-plot factor in 2009-2010 and 2010-2011 growing seasons. There were two water regimes: W1 (irrigation of 75 mm water at stem elongation stage) and W2 (irrigation of 75 mm water at stem elongation stage plus 75 mm at anthesis), and five nitrogen (N) treatments: 120+210 kg ha ^-1 (N4, traditional N application rate with pre-sowing N and top-dressed N at elongation), 120+150 kg ha ^-1 (N3), 120+90 kg ha ^-1 (N2), 120+0 kg ha ^-1 (N1), and 0+0 kg ha ^-1 (N0). Grain yield and dry matter remobilization amount, dry matter remobilization efficiency, contribution rate of dry matter remobilization to grain of individual organs of wheat plant were analyzed. Compared with N4, the treatments of decreased N rate increased the amount, efficiency and contribution rate to grain of dry matter remobilization in vegetative organs, among them the dry matter remobilization amount of chaff increased by 323.2%, which was higher than that of stem (24.5%) and leaf (4.6%), as well as dry matter remobilization efficiency and contribution rate of dry matter remobilization to grain in chaff increased by 313.7% and 77.0%, respectively, which were higher than those in stem (30.9% and 36.8%) and leaf (17.8% and 13.4%). The increase of dry matter remobilization from leaf in treatments of decreased N rates was mainly attributed to the increased dry matter remobilization amount from the 3rd leaf and 4th leaf, which was 28.7% and 201.1%, respectively. Similarly, the increase of dry matter remobilization from stem in treatments of decreased N rates was mainly attributed to the increased dry matter accumulation amount from the 2nd internode, the 3rd internode, the 4th internode and residue internodes, which was 21.7%, 71.8%, 44.5%, and 31.1%, respectively. There were no signi?cant differences in dry matter accumulation amount between W1 and W2, with slight higher dry matter remobilization efficiency in W1 (24.6%) than in W2 (23.8%), and higher contribution rate of dry matter remobilization to grain in W1 (35.1%) than in W2 (30.0%). Compared with W2, W1 reduced grain yield by 11.2% with a water reduction of 750 m ³ha ^-1. The results indicate that lower nitrogen supply enhances the dry matter remobilization from wheat vegetative organs to grains, improving the contribution rate of dry matter remobilization to grain, which is mainly contributed by chaff and lower layer organs (the 3rd leaf, the 4th leaf, the 3rd internode, the 4th internode and residue internodes), but not by upper layer organs.