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.