密度和施氮量对丘陵区机播夏玉米产量及倒伏影响研究

设置3个密度和3个施氮量处理,通过田间试验研究不同密度和氮肥用量对四川丘陵区机播夏玉米生长特征、产量及倒伏影响。结果表明,密度是影响玉米生长、产量和倒伏的主要因素。营养生长阶段玉米株高、抽雄吐丝期叶面积指数、群体生物量和有效穗随密度增加而增加,密度达7500株.hm-2提高穗着粒、百粒重、空秆率,降低穗长、结实长、穗粗、行数、行粒数。当密度为6000株.hm-2,施氮量375 kg.hm-2能获得最佳产量。夏玉米倒伏以茎折为主,茎折多发生在受密度和施氮量显著影响的基部第5节和第6节,密度为6000株.hm-2且施氮量375.hm-2能降低总倒伏率。

Effects of Planting Density and Nitrogen Application on Yield and Lodging of Mechanized Sowing Summer Maize

The effects of different planting density and nitrogen application on growth characteristics,yield and lodging of mechanized sowing summer maize were investigated in a field experiment in Sichuan hilly area.The results showed that the growth characteristics,yield and lodging were significantly correlated with density.The ear height during vegetative growth stage,leaf area index in the stamen-growing stage,population biomass,effective panicle number had an increasing trend respectively with density increasing.Under density of 7500 plants per hm2,the plant increased barren ratio,number of gain ear,100-kernel weight,and ear length,length of bearing kernel,ear diameter,rows per ear,kernels per row,were reduced compared with 4500 and 6000 plants per hm2.The yield reached an optimum when planting density was 6000 plants per hm2 and nitrogen application was 375 kg·hm2.Stalk breaking was the major form of lodging of summer maize,and it happened in the internode from bottom 5rd to 6th which was significantly affected by density and application levels of nitrogen.The treatment with density of 6000 plants per hm2 and nitrogen application of 375 kg·hm-2 could reduce root lodging percentage and stalk breaking percentage of summer maize.