密度和施氮量对超高产冬小麦群体质量和产量形成的影响

为明确种植密度和施氮量对超高产冬小麦群体质量和产量形成的影响,以冬小麦品种石麦18为材料,于2013-2014年度在河北省藁城市进行了密度(基本苗150万、225万、300万和375万·hm-2)和施氮量(180、240和300kg·hm-2)的二因素裂区试验。结果表明,小麦各生育时期群体总茎(穗)数随密度的增加而增加,但4种密度下都取得了较高的穗数。越冬前至开花期叶面积指数(LAI)和干物质积累量均随密度的增加而增加,但基本苗为150万和225万·hm-2时开花后LAI和干物质积累量都高于基本苗300万和375万·hm-2。各生育时期(除起身期外)不同施氮量之间总茎数差异不显著。干物质积累量随着施氮量增加呈增加趋势,高施氮量下开花后LAI衰减较慢。密度对产量及其构成因素的影响均显著,施氮量仅对千粒重和产量的影响显著;密度与施氮量对千粒重和产量有显著的交互效应。基本苗150万·hm-2、施氮量240~300kg·hm-2处理的小麦产量最高,分别为10 308.65和10 221.98kg·hm-2。因此,建议在低密度下适当增施氮肥。而从节本增效考虑,在高密度下应适当减少氮肥投入,以实现小麦的高产高效。

Effect of Planting Density and Nitrogen Application Rate on Population Quality and Yield Formation of Super High Yielding Winter Wheat

In order to clarify the effect of planting density and nitrogen fertilization application rate on population quality and yield formation of winter wheat,a field experiment was carried out at Gaocheng county,Hebei province,during 2013-2014,using a winter wheat cultivar,Shimai 18. The experiment was designed as split plot arrangement,with planting density as main plots (150×10⁴,225×10⁴,300×10⁴ and 375×10⁴ plants·hm^-2) and nitrogen fertilization rate as split plots (N 180,240 and 300 kg·hm^-2). The results showed that the amounts of population culms (spikes) of wheat increased with the increase of planting density during all growing stages,but all the four densities got enough spikes. The leaf area index (LAI) and dry matter accumulation during pre winter to anthesis increased with the increase of density,but the LAI and dry matter accumulation under 150×10⁴ and 225×10⁴ plants·hm^-2 were higher than those of 300×10⁴ and 375 ×10⁴ plants·hm^-2 during post anthesis period. The difference of the population culms at all growing stages (except erecting stage) was not significant among the three nitrogen fertilization rates. The dry matter accumulation had a tendency to increase with the increase of nitrogen rates,and the LAI of wheat with higher nitrogen fertilization rates declined slowly after anthesis. The effect of planting density on yield and its components of wheat were statistically significant (P<0.05). And the effect of nitrogen fertilization rate on 1 000 grain weight and grain yield were also statistically significant (P<0.05). The interactions of planting density and nitrogen rate on grain weight and grain yield were significant. The highest grain yields of wheat,10 308.65 and 10 221.98 kg·hm^-2,were achieved in the treatments with the planting density 150×10⁴ plants·hm^-2,and the nitrogen fertilization rates 240 and 300 kg·hm^-2,respectively. According to the results,it is recommended that,nitrogen fertilization should be increased properly under low planting density. Considering saving cost and improving nitrogen use efficiency,nitrogen input should be decreased under high planting density,so as to realize high yield and high efficiency of wheat production.