种植密度对棉花干物质、氮素累积与分配的影响

Effects of planting density on dry matter and nitrogen accumulation and distribution of cotton

2008~2009年设置6个密度处理,探讨不同种植密度对棉花（Gossypium hirsutum L.）开花后干物质及氮素累积与分配动态变化的影响,为长江流域下游棉区的合理密植提供理论依据。结果表明：棉花初花后群体干物质和氮素累积量随生育进程推延而呈Logistic曲线关系;种植密度显著影响干物质与氮素动态变化模型的特征参数,提高种植密度可使棉花干物质与氮素快速累积的起始日提早,但干物质与氮素快速累积速率以1hm 230000株处理较高、持续时间长、干物质与氮素累积量最多、生殖器官的分配指数最大、产量最高。综合分析显示,长江流域下游棉区抗虫杂交棉最适密度为1hm 230000株,在此密度条件下棉花干物质与氮素累积动态特征参数最为协调。

In order to explain the optimal planting density of cotton in the production area of lower reaches of Yangtze River Valley,a trial with 6 density levels in 2008 and 2009 was conducted to studied the effects of planting density on the dynamic changes of dry matter and nitrogen accumulation and distribution of cotton throughout the growth period after flowering.The results showed that the general pattern of cotton dry matter and nitrogen accumulation followed a Logistic function.The eigenvalues of the dynamic accumulation model of dry matter and nitrogen accumulation and distribution were affected significantly by the planting density.The initiations of cotton dry matter and nitrogen accumulation were shifted to an earlier time with increasing planting density.However,the medium density treatment（30 000 plants per hectare） was the optimal,with the highest speed and the longest time duration of cotton dry matter and nitrogen accumulation,the largest amount of dry matter and nitrogen accumulation,the highest distributive indexes of reproductive organ,and the highest yield.All results suggested that medium density（30 000 plants per hectare） was the optimal planting density in the cotton production area of lower reaches of Yangtze River Valley.