长期秸秆覆盖条件下施氮对冬小麦生长的影响

通过9年定位试验,研究了秸秆覆盖(不覆盖和秸秆覆盖4 500 kg·hm~(-2))和施氮量(0、75、150、225、300 kg·hm~(-2))对冬小麦群体动态、产量三要素和籽粒产量的影响。结果表明,秸秆覆盖显著降低冬小麦越冬期分蘖数和春季总茎数,越冬期分蘖数最多降低24%,春季总茎数最大降幅为40.7%;秸秆覆盖导致单位面积穗数减少,平均降幅5.6%,但穗粒数有增加趋势,对千粒重无显著影响;与无覆盖相比,秸秆覆盖的冬小麦籽粒产量略有降低。无论秸秆覆盖与否,小麦越冬期分蘖数、春季总茎数以及单位面积穗数均与施氮量呈抛物线的关系,穗粒数随施氮量的增加而增加,千粒重则随施氮量增加而降低;施用氮肥使小麦籽粒产量最高增幅接近70%;在供试条件下,秸秆覆盖无增产效应。相比秸秆覆盖,同样小麦产量水平下,常规栽培需氮肥较少。

Effects of nitrogen rate on the growth of winter wheat under long-term straw mulching

A 9-year-long field experiment from 2004—2013 was carried out to investigate the effects of straw mulch (no mulch and straw mulch 4 500 kg·hm-2 ) and N rate (0 ,75 ,150 ,225 and 300 kg·hm-2 ) on population dynamics , yield components and grain yield of winter wheat .The results showed that straw mulch significantly reduced overwintering tillers and total stem number in spring .Overwintering tillers and total stem number in spring under straw mulch reduced 24% and 40 .7% compared with no mulch respectively .Straw mulch led to slight decrease (5 .6% ) of ears per hectare and slight increase of grain number per spike .1000 grain weight had no significant change with straw mulch .A declining trend of wheat yield for straw mulch treatments was found compared to no mulch treatments .Regardless of no mulch or straw mulch ,the relationships between overwintering tillers ,total stem number in spring ,ears per hectare and nitrogen fertilizer rate could be described by parabolicfunction .Grain number per spike increased while 1000 grain weight de-creased with the increase of nitrogen rate .Application of nitrogen fertilizer almost increased grain yield by 70% compared to no nitrogen fertilizer input .No mulch treatments had higher wheat yield with less nitrogen fertilizer than straw mulch treatments .Straw mulch is not a good choice for improving winter wheat growth in this area .