氮素对滨海盐土棉花产量、品质及生物量的影响

为研究不同施氮量对滨海盐土花后棉株生物量、生物量累积特征及其与产量、品质的关系,于2010年和2012年在江苏滨海盐土设置了氮肥水平试验。结果表明:在0~600 kg·hm-2范围内施氮量越大棉株总生物量累积越多,而皮棉产量2010年和2012年分别在施氮375 kg·hm-2和300 kg·hm-2时达到最大;成铃数在施氮300~375 kg·hm-2范围内达到最大;铃重和衣分随施氮量增加而增加,达到最大值后(≥300 kg·hm-2)差异不显著。在300~375 kg·hm-2施氮量范围内纤维比强度最高;高氮有利于上部、顶部果枝纤维长度、比强度、伸长率的提高和马克隆值的优化,但显著降低中下部果枝棉纤维比强度,导致中部纤维马克隆值变劣、下部果枝纤维伸长率下降,说明高氮对中下部果枝棉纤维品质的形成利弊各半,适量高氮可提高上部及顶部果枝产量、品质。在滨海盐土条件下,利于产量、品质及氮素利用效率提高的适宜施氮量为375 kg·hm-2。

Effect of N Application Rate on Growth,Yield and Fiber Quality of Cotton Grown in Saline Coastal Land

Field experiments were carried out at Dafeng experimental station (33.2°N, 120.5°E) in 2010 and 2012 to study the effects of N application rates on cotton growth, cotton yield and fiber quality by applying six levels (0, 150, 300, 375, 450, 600 kg·hm^－2) of N fertilization in the saline coastal soil. The results showed that: in the 0-600 kg·hm^－2 application range, the plant biomass increased with the increasing of N application rate. The highest cotton yield in 2010 and 2012 were obtained under the 375 and 300 kg·hm^－2 nitrogen application rate, respectively. For yield components, the highest boll number was obtained under 300 and 375 kg·hm^－2 nitrogen application rates; Boll weight and lint percentage increased with the increase in nitrogen application rate at the 0-300 kg·hm^－2 levels, and then maintained a steady level at the 300-600 kg·hm^－2 N application rates. The highest fiber strength was obtain in 300 and 375 kg·hm^－2 nitrogen application treatments. High nitrogen application rate (＞375 kg·hm^－2) increased the fiber length, strength, elongation ratio, and optimized micronaire value of bolls on upper and top fruiting branches; while it was disadvantageous to fiber quality of bolls on middle and bottom fruiting branches. Taken together, we concluded that using N fertilizer at an application rate of 375 kg·hm^－2 could balance the requirements of high yield, high quality and high N efficiency in saline coastal land around the experimental station.