施氮量对花铃期棉花果枝生物量累积时空变异特征的影响

试验在黄河流域黄淮棉区的河南安阳和长江流域下游棉区的江苏南京棉花大田进行， 氮素设0（N₀）、120（N₁）、240（N₂）、360（N₃）、480（N₄） kg·hm^-2 5个水平，定量分析了不同施氮量对美棉33B花铃期棉花果枝生物量累积时空变异特征的影响.结果表明： 不同施氮量下，两试验点棉株不同果枝部位营养器官、生殖器官、生物量累积时间变异特征均表现为Logistic曲线，空间变异特征存在明显差异.安阳点360 kg·hm^-2施氮量、南京点240 kg·hm^-2施氮量处理具有快速增长期起始时间早、持续时间短、最大速率大等特征，说明该施氮量水平有利于棉花生物量的快速累积，以形成较高的产量与品质；而施氮量过多或不足均不利于棉株不同果枝部位生物量的累积.可以通过不同的施氮量来调节棉株不同果枝部位快速生长期的生长特征值，以提高棉花的产量和品质.

Effects of nitrogen application rate on spatiotemporal variability of biomass accumulation of cotton's fruiting branch at flower and boll stage

Field experiments were conducted in Anyang and Nanjing, the typical representatives of ecological regions in the Yellow River Valley and the lower reaches of Yangtze River Valley in China, to quantitatively analyze the spatiotemporal variability of biomass accumulation of the fruiting branch of cotton variety Nucotn 33B at its flower and boll stage under effects of 0, 120, 240, 360, and 480 kg N·hm^-2 (marked as N₀, N₁, N₂, N₃, and N₄, respectively). The results indicated that both in Nanjing and in Anyang, the temporal variability of biomass accumulation of vegetative and reproductive organs at different positions of fruiting branch could be described by Logistic equation, but the spatial variability was obviously different. Under the nitrogen application rate of 360 kg·hm^-2 in Anyang and of 240 kg·hm^-2 in Nanjing, the biomass accumulation had the characteristics of earlier starting date, shorter duration, and maximal speed of rapid increase. These nitrogen application rates could accelerate the biomass accumulation to benefit the high lint yield and fiber quality, while excess or deficient nitrogen supply was disadvantageous to the biomass accumulation of fruiting branch. Therefore, it could be possible to apply appropriate amount of nitrogen to regulate the growth eigenvalues of different positions fruiting branch at its speed growth stage to obtain high lint yield and fiber quality.