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以早熟棉中棉所50为材料进行麦后直播棉花试验,研究施氮量(0、60、120、150、180、240kg N·hm~(-2))对棉株氮素吸收、利用和分配的影响.结果表明:增施氮肥提高了麦后直播棉不同生育阶段的氮吸收量,以盛花到见絮期的氮积累增量最大,并且改变了不同生育期间氮吸收比例,使棉花出苗到盛花期的氮吸收比例降低,盛花到吐絮期的氮吸收比例升高;增施氮肥还降低了生育后期中上部位果枝氮浓度的下降速率.麦后直播棉氮素和生物量累积以中下部果枝为主,在150-180 kg N·hm~(-2)施氮量下棉花产量、氮肥表观利用率、各果枝部位干物质和氮在生殖器官中的分配比例较高,氮浓度和氮累积量动态特征参数比较协调.高于180kg N·hm~(-2)的施氮量导致棉花中部和下部果枝生殖器官生物量和氮素累积量、产量增幅和氮肥利用率降低,而低于150 kg N·hm~(-2)施氮量降低棉花整株干物质和氮经济系数,不利于高产形成.综合分析,150~180kg N·hm~(-2)施氮量可作为长江流域下游棉区麦后直播棉的推荐施氮量.
Cotton (Gossypium hirsutum L.) was used as raw material to conduct direct seeding cotton experiment after wheat germplasm to study the effect of nitrogen application rate (0, 60, 120, 150, 180 and 240 kg N · hm -2) The results showed that nitrogen application increased the nitrogen uptake in different growth stages of direct seeding cotton and increased the nitrogen accumulation increment from full bloom to full bloom, and changed the ratio of nitrogen uptake during different growth stages, The proportion of nitrogen uptake to the full flowering stage decreased and the percentage of nitrogen uptake increased from full flowering stage to boll opening stage.The increase of nitrogen application also decreased the rate of decline of nitrogen concentration in middle and upper branch of post growth stage The lower part of fruiting branches was the main part. Under the nitrogen application rate of 150-180 kg N · hm -2, the cotton yield, the apparent nitrogen use efficiency, the distribution proportion of dry matter and nitrogen in reproductive organs were higher, and the nitrogen concentration And the dynamic characteristic parameters of nitrogen accumulation were more harmonious.The nitrogen application above 180 kg N · hm -2 resulted in lower reproductive organs biomass and nitrogen accumulation, lower yield and nitrogen use efficiency in middle and lower cotton branches The nitrogen application rate of less than 150 kg N · hm -2 reduced whole plant dry matter and cotton Economic factor, is not conducive to the formation of high-yield comprehensive analysis, 150 ~ 180kg N · (-2) nitrogen application rate hm ~ downstream Yangtze River Region as recommended nitrogen rate broadcast cotton after wheat.