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为探明秸秆还田条件下机插稻适宜施氮量,阐明机插稻产量和高质量群体形成对氮肥响应的特点,在大田秸秆全量还田条件下,以优质食味水稻南粳9108为材料,设置0、135.0、202.5、270.0、337.5、405.0kg/hm2等6种施氮水平,研究氮肥用量对机插稻产量及其构成和群体质量的影响。结果表明,随着施氮量增加,机插稻产量先增加后减少,以施氮量为270kg/hm2产量最高。产量提高的主要原因是较高的群体颖花量,在施氮量为270kg/hm2条件下,机插稻群体颖花量达最大值。机插稻单位面积穗数随着施氮量增加而增加,每穗粒数先增后减,而结实率和千粒重表现为递减趋势。随着氮肥用量增加,机插稻分蘖中期、拔节期、抽穗期和成熟期的茎蘖数、叶面积指数、光合势和干物质积累量均呈递增趋势,而抽穗后干物质积累量、成穗率、有效叶面积率、高效叶面积率和粒叶比呈先增后降的趋势。因此,秸秆还田后适当增加施氮量利于提高机插稻产量,优化群体质量。
In order to find out the suitable nitrogen application rate of machine-inserted rice under straw-returning condition, and to explain the characteristics of machine-inserted rice yield and high-quality group formation on nitrogen fertilizer response, , And six nitrogen application rates (0,135.0,202.5,270.0,337.5,405.0kg / hm2) were set up to study the effects of nitrogen rates on the yield, composition and population quality of rice. The results showed that with the increase of nitrogen application, the yield of machine-inserted rice increased first and then decreased, with the highest yield of nitrogen application rate of 270kg / hm2. The main reason for the increase in yield was the higher population spikelet capacity. Under the nitrogen application rate of 270kg / hm2, the spikelet volume reached the maximum in the machine-inserted rice population. The number of panicle per unit area increased with the increase of nitrogen application rate, the number of grains per spike increased first and then decreased, but the seed setting rate and thousand kernel weight showed a decreasing trend. With the increase of nitrogen application rate, the tiller number, leaf area index, photosynthetic potential and dry matter accumulation at mid-tillering stage, jointing stage, heading stage and maturing stage showed an increasing trend, while the dry matter accumulation after heading Spike rate, effective leaf area ratio, high leaf area ratio and grain-leaf ratio at first increased and then decreased. Therefore, after returning straw to the appropriate increase of nitrogen application is conducive to improving the yield of rice, optimize group quality.