施氮量对油后直播棉花产量、品质及生物量的影响

为研究施氮量对油后直播棉花生物量累积特征及其与产量、品质的关系,于2016-2017年在湖南常德设置了施氮量分别为0、90、180、270、360 kg·hm^-2氮肥水平试验。结果表明,在施氮量为0~360 kg·hm^-2范围内,施氮量越大棉株营养器官生物量累积越多,而棉株生殖器官生物量则在施氮量为270 kg·hm^-2时累积最多;皮棉产量、成铃数和单铃重均在施氮量为270 kg·hm^-2时达到最大;0~270 kg·hm^-2范围内,衣分随施氮量增加而增加。在施氮量为270 kg·hm^-2条件下,纤维长度和断裂比强度最高;适宜施氮量有利于纤维长度、断裂比强度的提高和马克隆值的优化,对伸长率和整齐度基本无影响。综上所述,适宜施氮量可提高棉花的产量、品质,洞庭湖棉区适宜的施氮量为180~250 kg·hm^-2。本研究结果为环洞庭湖棉区的氮肥合理运筹提供了技术参考。

Effect of N Application Rate on Growth,Yield and Fiber Quality of Direct Seeding Cotton After Rape Harvest

In order to study effects of five nitrogen application rates(0,90,180,270,360 kg·hm^-2)on biomass accumulation, growth rate, yield and fiber quality of direct sowing cotton rape was investigated in this study by applying field experiments at Changde in 2016 and 2017. The results showed that the biomass accumulation of vegetative organs was positively correlated with nitrogen application rate in the range of 0~360 kg·hm^-2. The biomass of reproductive organs accumulated the most at 270 kg·hm^-2, furthermore, lint yield, boll number and boll weight reached the maximum when applied at 270 kg·hm^-2 nitrogen application rate. The lint percentage was positively correlated with nitrogen application rate in the range of 0~270 kg·hm^-2, but there were no differences among all the treatments. Under the condition of 270 kg ·hm^-2 nitrogen application rate, the fiber length and breaking ratio strength were the highest. It was concluded that the yield and quality of cotton could be improved by applied appropriate nitrogen application rate which was beneficial to the improvement of fiber length, breaking ratio strength and micronaire, while appropriate nitrogen had no effect on the elongation and uniformity. The results of this study provide technical references for the rational management of nitrogen fertilizer in cotton areas around Dongting Lake.