拔节期追氮对鲜食糯玉米产量和花后养分积累转运的影响
摘要：【目的】植株需氮与供氮之间的异步不仅降低玉米产量，同时增加环境风险，合理追氮有利于实现高产与高效间的协调。【方法】以苏玉糯5号和渝糯7号为材料，2013-2016年于扬州大学实验农场研究了拔节期追氮量（0、150和300 kg hm-2）对鲜食糯玉米产量（鲜果穗和鲜籽粒）、干物质和氮素积累和转运的影响。【结果】结果表明，鲜食糯玉米籽粒产量和果穗产量均随追氮量的增加呈先升后降趋势，在追氮150 kg hm-2时产量最高。干物质和氮素积累量随着追氮量的增加表现趋势与产量一致。氮素利用率（产量/植株吸氮量）以籽粒作为收获产品时随追氮量增加逐渐降低，而以果穗作为收获产品时在150和300kg hm-2时无显著差异，但低于不追氮处理。【结论】因此，在鲜食糯玉米生产中，拔节期适量追氮（150kg hm-2），可有效增加鲜食糯玉米产量、后期干物质和氮素积累量以及氮素利用效率，提高产量的同时降低环境风险。
英文摘要:
Abstract: [objective] The asynchronism between plant N demand and N supply not only reduce maize yield, but also increase environmental risk. Topdressing the N timely and fittingly could achieve the balance between high yield and high efficiency. [Method] The effects of N rates (0, 150 and 300 kg ha-1) topdressing at jointing stage on fresh waxy maize yield (ear and grain) and accumulation and translocation of dry matter and N post-flowering were studied using the control varieties in south China (Suyunuo 5 and Yunuo 7) as materials at Yangzhou experimental farm in 2013-2016. [Result] The fresh waxy maize ear and grain yield rose first and fall later and peaked at 150 N kg ha-1. The change tends of dry matter and N accumulation under different N rates was similar to yield. The N use efficiency (yield/ N absorption) gradually reduced with the increase of N rates when the harvest product was grain, while the value was similar between N rates 150 kg ha-1 and 300 kg ha-1 and lower at N 0 kg ha-1 when the harvest product was ear. [Conclusion] In fresh waxy maize production, the appropriate N topdressing at jointing stage was about 150 kg ha-1, which increased the yield of fresh waxy maize (ear or grain) and the dry matter and N accumulation post-flowering, ultimately increased the yield and reduced environmental risks.
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