本文以棉花早熟品种“JX0010”为实验材料，采用二次最优回归设计（311设计），研究了施氮量、种植密度、播种期对棉花干物质积累和分配的影响。结果表明：棉花单株营养器官与生殖器官干物质积累动态基本一致，符合“S”型曲线变化规律，生长前期积累速度缓慢，中期积累速度加快，后期干物质积累趋于平缓。种植密度是影响干物质积累的主要因子，施氮量次之，播种期影响最小。单株营养器官干物质积累随施氮量的增加、播种期的推迟出现先上升后下降的趋势，随密度的增加而下降；单株生殖器官干物质积累随施氮量增加而上升，随密度增加和播种期推迟而减少。各处理棉花群体干物质积累随着生育进程的推进而逐渐增加，以处理9群体干物质总量最大，达到20 640 kg/hm²，比其他处理高15.74%-137.48%。

Early maturing cotton variety “JX0010” was used in this research as test material The effects of nitrogen concentration, density and planting period on the accumulation and distribution of cotton dry matter were studied by using the quadratic optimal regression design（311 design）The results showed that: The accumulation of dry matter accumulation of cotton single plant and reproductive organs is basically consistent with the change of “S” curve The dry matter accumulation was relatively slow in the early stage of the growth, and actually accelerated in the middle stage The dry matter accumulation at the later stage began to flatten The density is the main factor that affects the accumulation of dry matter The accumulation of dry matter of single vegetative organs increases with the increases with the increase of nitrogen fertilizer, and the delay of planting time increases first and then decreases, and decrease with increasing density The accumulation of dry matter of single plant reproductive organs increased with the increase of nitrogen and decreased with the increase of density and delay of planting time The cotton population dry matter accumulation increased with the advancement of growth period, and had biggest value in the 9th treatment (20 640 kg/hm2) and increased by 15.74%-137.48% than other treatments