不同灌水条件下施氮量对滴灌夏棉冠层指标的影响

目的]揭示施氮量对滴灌夏棉冠层指标的调控作用。方法]设置3个灌水水平(滴灌,灌水定额30、22.5、15mm,分别记为I1、I2、I3)和5个氮素水平(0、60、120、180、240kg/hm2,分别记为N0、N1、N2、N3、N4),研究了不同灌水条件下施氮量对株高、叶面积指数、叶片含氮量和比叶重的影响。结果]I2条件下,株高和叶面积指数随施氮量增加呈不断增加趋势,施氮量为240kg/hm2时达到最大。I1和I3条件下,增加施氮量,株高和叶面积指数先增加后减小,在施氮量为60或120kg/hm2的处理达到最大。夏棉比叶重和叶片含氮量随着生育期推进分别呈不断上升和不断下降趋势,5个施氮水平下夏棉叶片比叶重均表现为I1

Response of Canopy Traits of Summer Cotton to Different Fertigations

【Objective】This paper aims to investigate the impact of different combinations of irrigation schedule and nitrogen application on canopy traits of summer cotton.【Method】The experiment was conducted at a field under drip irrigation in Xinxiang of Henan province. We compared three irrigation amounts: 30(I1), 22.5(I2) and15 mm(I3), and five nitrogen applications: 0(N0), 60(N1), 120(N2), 180(N3) and 240 kg/hm~2(N4). In each treatment, we measured plant height, leaf area index(LAI), leaf nitrogen content(LNC) and specific leaf weight(SLW).【Result】When the irrigation was 30 mm, plant height and LAI increased with nitrogen application up to240 kg/hm~2. When the irrigation was 30 mm and 15 mm, the plant height and LAI firstly increased with nitrogen application up to 120 kg/hm~2 and then declined with a further increase in nitrogen application. As the plant grew,SLW monotonically increased while the LNC declined. In all nitrogen treatments, the SLW increased as irrigation amount decreased. Correlation analysis revealed that the yield and LAI were best correlated with R~2=0.7035,while the yield and SLW was worst correlated with R~2=0.072 6.【Conclusion】Nitrogen application significantly increased plant height, LAI and LNC. Water deficit effectively increased the SLW at flowering-bolling stage. The seed-yield and LAI was best correlated, implicating that LAI can be used as an indicator to predict summer cotton production.