不同密度下施氮量对夏玉米产量及强弱势子粒发育的影响

以京农科728为材料,探讨不同密度下施氮量对夏玉米产量及强弱势子粒发育的调控效应。结果表明,增密和施氮显著提高产量5.3%～28.3%和8.5%～26.0%。子粒鲜体积、鲜重和干重强弱势子粒间均表现为下部>中部>上部。施氮后子粒鲜体积、鲜重和干重显著提高0.2%～45.5%、0.1%～33.3%和0.4%～95.3%。增密强势子粒鲜体积降低1.0%～1.7%,鲜重提高9.4%～9.6%,弱势子粒分别降低7.1%和5.5%。综上,在夏玉米延迟收获条件下,施氮提高粒重而提高产量;增密导致弱势子粒粒重降低但强势子粒粒重提高实现增产;施氮和增密提高子粒脱水速率,达到子粒机收含水率标准,为华北平原夏玉米产量形成和机械直收提供支撑。

Effects of Nitrogen Application on Summer Maize Yield and Superior and Inferior Grain Development at Different Densities

In order to investigate the effects of nitrogen application rate on summer maize grain yield and superior and inferior grain development under different densities, Jingnongke728 was used in this study. The results showed that, increased density and Nitrogen application significantly enhanced grain yield 5.3%-28.3% and 8.5%-26.0%, respectively. Superior and inferior grain fresh volume, fresh weight and dry weight were played as lower > middle > upper. The grain fresh volume, grain fresh weight and grain dry weight were significantly increased by 0.2%-45.5%, 0.1%-33.3% and 0.4%-95.3% after nitrogen application. With the increase of density, the fresh volume of superior grains decreased by 1.0%-1.7%, the fresh weight increased by 9.4%-9.6%, and inferior grains decreased by 7.1% and 5.5%, respectively. In conclusion, summer maize under delayed harvest condition, nitrogen application could improved grain weight, so increased grain yield significantly. Increased density leads to the decrease of inferior grain weight, while superior grain weight and grain yield increased. Grain dehydration rate were significantly increased by Nitrogen application and density increased, which led to summer maize reached the water content standard of grain mechanical harvesting, so this study could provided theoretical support for summer maize yield formation and grain mechanical harvesting in the North China Plain.