氮肥减施对宽幅播种冬小麦产量形成和氮肥利用效率的影响

为明确氮肥减施对宽幅播种冬小麦产量和氮肥利用效率的影响,设置氮肥减施(减肥处理)、农户习惯施肥量(习惯施肥处理)、不施氮(无肥处理)3个处理,通过大田试验研究了不同处理冬小麦的群体动态、干物质积累特征、产量及其构成和氮肥利用效率的影响。结果表明,无肥处理的产量比习惯施肥处理低36.83%,而减肥处理的产量比习惯施肥处理高6.01%。无肥处理的最大茎蘖数显著低于习惯施肥处理,导致亩穗数和收获期生物量显著低于习惯施肥处理。减肥处理的最大茎蘖数也显著低于习惯施肥处理,但由于成穗率显著提高,亩穗数和收获期生物量与习惯施肥处理无显著差异。无肥处理的有穗单茎花后干物质积累量、花后干物质对籽粒的贡献率与习惯施肥处理无显著差异。而减肥处理的花后干物质积累量、花后干物质积累对籽粒的贡献率比习惯施肥处理分别显著提高39.70%和14.51个百分点。减肥处理的地上部氮吸收量与习惯施肥处理无显著差异,但氮收获指数提高2.97%,氮肥农学效率提高12.94%,氮肥偏生产力提高41.09%,氮肥利用率提高11.90个百分点。上述试验结果表明,宽幅播种配合氮肥减施可通过降低最大茎蘖数,提高成穗率,促进花后干物质积累及向籽粒分配,提高氮肥利用效率和产量。本研究为宽幅播种冬小麦实行氮肥减施提供了科学依据。

Effects of Reduced Application of Nitrogen Fertilizer on Yield Formation and Nitrogen Use Efficiency of Winter Wheat With Wide-Range Sowing

In order to explore the effects of reduced application of nitrogen fertilizer on grain yield and nitrogen use efficiency of winter wheat with wide-range sowing, field experiments was conducted during the winter wheat growing season in 2018-2019. Three treatments including reduced rate of nitrogen fertilizer (RNF), conventional rate of nitrogen fertilizer (CNF), and no nitrogen fertilizer (N0) were applied to investigate the dynamic of shoot number, dry matter accumulation, grain yield and its component, nitrogen use efficiency of winter wheat. Results showed that the grain yields of N0 were 36.83% lower than that of CNF, and the grain yields of RNF were 6.01% higher than that of CNF. The maximum shoot number per hectare in N0 was significantly lower than that in RNF, which resulted in significantly lower number of the spike per hectare and the biomass in the harvest period than in RNF. The maximum shoot number per hectare in CNF was also significantly lower than that in RNF. While the spike rate was significantly increased, the spike number per hectare and the biomass during harvest were not significantly different from those in CNF. There was no significant difference between the dry matter accumulation after anthesis and the contribution rate of the dry matter accumulation after anthesis to the grains in N0 and that in CNF. The dry matter accumulation after anthesis and the contribution rate of the dry matter accumulation after anthesis to the grains of CNF were 39.70% and 14.51 higher than that of RNF. The nitrogen uptake of above-ground part in RNF was not significantly different from that of CNF. However, compared with CNF, the nitrogen harvest index increased by 2.18%, the nitrogen agronomic efficiency increased by 12.94%, the nitrogen partial productivity increased by 41.09%, and the nitrogen use efficiency increased by 11.90% in RNF, respectively. This indicates that wide-range sowing combined with reduced nitrogen fertilizer application can reduce the maximum shoot number, increase the spike rate, promote the accumulation of dry matter and distribution to the grains after antheis, so as to increase the nitrogen fertilizer use efficiency and yield. This study provides a scientific basis for winter wheat planting with wide range sowing to reduce the applicat of nitrogen fertilizer.