Abstract: This paper used ‘Xinluzao 57’ as material, and studied the effects of different nitrogen application rates (0, 100, 200, 300, 400 kg·hm^-2) on the nutrient accumulation and distribution of cotton between chemical topping and manual topping. The results showed that: when the nitrogen application rate reached 300 kg·hm^-2, the aboveground accumulation of dry matter and nitrogen in the chemical topping  still increased slightly, while  decreased in the manual topping. In the chemical topping treatment, the rapid accumulation period of dry matter was 59~109 d after emergence, while was 56~100 d in the artificial topping after emergence. In the late growth stage of cotton (30~60 d after topping), the aboveground dry matter accumulation and nitrogen accumulation in chemical topping were higher than that in manual topping  under the same nitrogen application rate. The optimum nitrogen application rate was 300 kg·hm^-2, the number of bolls per plant was significantly increased by 0.66~1.66, with an average yield increase of 26.72%.

Key words: cotton, chemical toppping, nitrogen fertilizer, dry matter accumulation

摘要： 以‘新陆早57号’棉花品种为试验材料，研究了不同施氮量（0、100、200、300、400 kg·hm^-2）对化学封顶与人工打顶下棉花营养积累与分配等的影响。结果表明：在施氮量达到300 kg·hm^-2后，化学封顶棉花地上部分干物质积累量和氮素积累量仍有小幅增长，而人工打顶棉花呈现下降趋势。棉花干物质快速积累期化学封顶处理为出苗后59~109 d，而人工打顶为出苗后56~100 d。在棉花生育后期（打顶后30~60 d），同等施氮量条件下化学封顶棉花地上部分干物质积累量及氮素积累量高于人工打顶棉花。该研究最佳施氮量为300 kg·hm^-2时，可显著增加棉花单株结铃数0.66~1.66个，平均增产26.72%。

关键词: 棉花, 化学封顶, 氮肥, 干物质积累量