Abstract: [Objective] The project aims to explore the interaction effect of chemical topping and water on cotton,the effects of different drip irrigation amount on canopy structure,dry matter distribution and yield of the chemical topping cotton in order to provide theoretical basis for chemical topping technology.[Method] Under the natural conditions in the field,the artificial topping was used as the control,and two topping agents,the combination of fluorine amine compound and DPC,were selected.After applying the topping agent,two drip irrigation (routine irrigation),middle drop water quantity (85; normal irrigation volume) and low drop water quantity (70; regular irrigation amount) were set up and after that,3 different water drop amount were applied.The leaf area index of different cottons were determined in different parts of the canopy light transmittance,dry matter accumulation and yield components in different conditions;The canopy characteristics,light distribution,material allocation and yield change of chemical topping cotton were analyzed under different drip irrigation conditions.[Result] Chemical topping cottons had the high leaf area index (LAI) and the longest duration,under middle drip irrigation which led to the increase of the photosynthetic area,and the appropriate DIFN,light distribution and canopy structure were beneficial to increase the light efficiency.The higher dry matter improved proportion percentage of photosynthetic material to reproductive organs.The lower drip irrigation amount also decreased the cost compared with the high drip irrigation.And the middle drip irrigation amount treatment significantly increased seed cotton yield compared to the low drip irrigation amount treatment.[Conclusion]Therefore,the two irrigation should be controlled in middle drip volume (32m3/667 m2) after spraying topping agent,which can not only optimize chemical topping cotton canopy structure,but also promote photosynthetic material to the reproductive organ allocation and give full play to water-saving irrigation under mulch,and increase the efficiency and productivity.

摘要： [目的]研究化学打顶剂与水分对棉花的交互效应,分析不同滴水量对化学打顶棉花冠层特征、物质积累与分配及产量的影响,为棉花化学打顶技术推广提供理论依据.[方法]田间自然条件下,以人工打顶作为对照,选用氟节胺复配型和缩节胺复配型两种打顶剂,于喷施打顶剂后的两次灌水分别设高滴水量(常规灌量)、中滴水量(85;常规灌量)和低滴水量(70;常规灌量)3种不同滴水量.分别测定不同处理棉花叶面积指数、冠层各部位透光率、干物质积累量及产量构成因素;分析在不同滴水量条件下,化学打顶棉花的群体冠层特征、光分布、物质分配及产量变化.[结果]中滴水量处理下,化学打顶棉花群体叶面积指数高且持续期长,增加了光合面积.冠层开度适宜,光分布合理,冠层不遮蔽,有利于提高光能利用率.干物质积累量较大且提高了物质向上部生殖器官的分配比例;且相对于高滴水量处理灌量较少,减少了灌溉成本;相对于低滴水量处理显著提高了棉花籽棉产量.[结论]喷施打顶剂后的两次灌水控制在中滴水量(32 m3/667 m2)可以优化化学打顶棉花冠层结构、促进光合物质向生殖器官分配,充分发挥膜下滴灌节水、增效和增产潜力.