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采用三因素二次饱和Ｄ—最优设计方法，研究了春玉米子粒建成期间子粒干重的变化及播期、密度、施氮量对其影响，阐明了春玉米子粒建成期间干物质积累Ｓ形曲线的数量变化。通过聚类分析可划分为指数增长期（授粉后１９天内），直线增长期（授粉后２０～４３天），缓慢增长期（授粉４４天至成熟）；子粒干物质增长速度为单峰曲线，但播期晚、高密度、高施氮量处理下峰值较小，峰值之后干物质积累速度下降快；晚播处理下子粒子物质积累的指数增长期延长，直线增长期缩短，产量显著下降。
The effects of sowing date, planting density and nitrogen application on the dry weight of spring maize during grain filling were studied by using the three-factor secondary saturation D-optimal design method. The number of curves changes. The clustering analysis can be divided into exponential growth period (19 days after pollination), linear growth period (20-43 days after pollination), slow growth period (44 days after pollination to maturity) However, the late sowing date had a small peak under the high-density and high-N treatments, and the dry matter accumulation rate decreased rapidly after the peak sowing. Under the late sowing treatment, the exponential growth period of the accumulation of PMs was prolonged, the linear growth period was shortened and the yield was significantly decreased.