机采棉模式下氮肥用量对棉花株型结构塑造和产量的影响

【目的】研究不同施氮量对机采棉株型塑造、冠层结构和产量的影响,分析适宜冀南棉区机采棉种植的氮肥用量。【方法】采用田间小区试验,设置0、60、120、180、240、300、360和420 kg/hm²共8个氮肥施用梯度,研究不同施氮量对冀南棉区机采棉株高、果枝数、果枝始节高度和节位、果枝长度、果枝节数、果枝夹角、吐絮率、叶面积指数、透光率、叶倾角和产量的影响。【结果】随着施氮用量的增加,棉花株高、果枝数、果枝长度和果枝夹角呈先升高后降低趋势,果枝始节高度呈先降低后升高趋势,棉花吐絮率随着施氮量的增加呈降低趋势,其中N₃~N₈没有显著差异。与不施氮相比,施氮处理可以增加棉花叶面积指数,降低叶倾角,使冠层有效光截获量显著增加。随着施氮量的增加,棉花单株铃数呈先增加后降低趋势,单铃重呈增加趋势,棉花籽棉产量随氮肥用量增加而增加,N₆~N₈差异不显著。【结论】氮肥用量会显著影响棉花适宜机采农艺性状,影响棉花株型塑造、群体冠层结构和产量,冀南棉区机采棉的氮肥推荐量为300 kg/hm²。

Effect of Nitrogen Application Rates on Plant Architecture and Yield of Cotton Production with Machine Picking in Hebei

【Objective】 To determine the effects of different nitrogen application rates on plant-type structure, canopy structure and yield of machine-picked cotton and then the suitable nitrogen application rate for the cotton planted in southern Hebei.【Method】 A field plot experiment was conducted to study the effects of different nitrogen application rates on plant-type structure, canopy structure and yield of machine-picked cotton by setting 8 nitrogen application gradients of 0, 60, 120, 180, 240, 300, 360 and 420 kg/hm².【Result】 With the increase of nitrogen application rate, cotton plant height, branches number, length of the fruit branches and fruit branch angle first increased and then decreased, first fruit branch height decreased and then increased, flocculation rate decreased with the increase of nitrogen application rate, and N₃ ~ N₈ treatments had no significant difference. Compared with no nitrogen application, nitrogen application could increase leaf area index, decrease leaf transmittance, and significantly increase canopy effective light interception. With the increase of nitrogen application rate, boll number per plant increased first and then decreased, boll weight increased, seed cotton yield increased with the increase of nitrogen application rate, and there was no significant difference between N₆ and N₈ treatment.【Conclusion】 The amount of nitrogen fertilizer can significantly affect the agronomic traits of cotton suitable for mechanical harvesting, plant-type structure, canopy structure and yield of cotton. The recommended amount of nitrogen fertilizer for machine-picked cotton in southern Hebei is 300 kg/hm².