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以淮北地区有代表性的34个中熟中粳品种为试材,设置7个氮肥水平(0、150.0、187.5、225.0、262.5、300.0、337.5 kg hm–2),得出各品种在这7个氮肥水平下出现的最高产量,将该最高产量定义为氮肥群体最高生产力。在此基础上,按氮肥群体最高生产力高低将品种划分为4个等级,即顶层水平(≥10.50 t hm–2)、高层水平(9.75~10.50 t hm–2)、中层水平(9.00~9.75 t hm–2)和底层水平(≤9.00 t hm–2),比较研究不同氮肥群体最高生产力等级品种的产量及其构成因素、群体光合物质生产和氮素吸收利用差异。结果表明,所有品种的氮肥群体最高生产力均出现在225.0、262.5、300.0 kg hm–2三个氮肥水平,不同氮肥群体生产力差异极显著;随着生产力水平的提高,单位面积穗数先增加后降低,每穗粒数与群体颖花量显著增加,结实率显著下降;茎蘖成穗率、叶面积指数、光合势、有效叶面积率、高效叶面积率、粒叶比、总干物质积累量均以顶层水平最高,底层水平最低;移栽至拔节阶段的氮素积累比例表现为底层>中层>高层>顶层水平,拔节至抽穗、抽穗至成熟阶段表现为顶层>高层>中层>底层水平;移栽至拔节、拔节至抽穗及抽穗至成熟阶段的氮素吸收速率以顶层最高,顶层水平较底层水平分别高36.59%、34.36%和51.85%;随着氮肥群体生产力等级的提高,氮素吸收利用率和百千克籽粒吸氮量均提高;中熟中粳稻品种有氮低效型、氮中效型、氮较高效型和氮高效型,武运粳27、中稻1号、宁粳4号、连粳7号为高产氮高效品种。
A total of 34 middle-maturing and medium-maturing japonica cultivars in Huaibei were used as experimental materials to set up 7 nitrogen fertilization levels (0,150.0,187.5,225.0,262.5,300.0,337.5 kg hm-2) The highest yield occurred at the level of N-fertilizer and the highest yield was defined as the highest productivity of N-fertilizer population. On this basis, the cultivars were divided into four grades according to the highest productivity of nitrogenous fertilizer group, namely, the top level (≥10.50 t hm-2), the top level (9.75-10.50 t hm-2), the middle level (9.00-9.75 t hm-2) and the bottom level (≤9.00 t hm-2). The yield and its components, the photosynthetic material production and nitrogen uptake and utilization of the highest productivity classes of different N fertilizer groups were compared. The results showed that the highest productivity of all nitrogenous fertilizer groups appeared at three nitrogen fertilization levels of 225.0,262.5 and 300.0 kg hm-2. The productivity of different nitrogenous fertilizer groups was significantly different. With the improvement of productivity, the panicle number per unit area increased first and then decreased , The number of spikelets per panicle and the number of spikelets increased significantly and the seed setting rate decreased significantly. The percentage of spikelets to panicles, leaf area index, photosynthetic potential, effective leaf area, high leaf area, grain-leaf ratio, total dry matter accumulation The highest level of the top layer and the lowest level of the bottom layer. The ratio of nitrogen accumulation from transplanting to jointing stage showed that the ratio of nitrogen accumulation from bottom layer to middle layer to top layer was from jointing stage to heading stage, and from top stage to top stage to middle stage and bottom stage, The nitrogen uptake rate from transplanting to jointing, jointing to heading and heading to mature stage was the highest in top layer, and the top layer was 36.59%, 34.36% and 51.85% higher than the bottom layer, respectively. With the improvement of nitrogen productivity, the nitrogen uptake Utilization rate and nitrogen uptake per 100 kg of grains were increased; middle-maturing varieties of japonica rice were inefficient nitrogen type, middle nitrogen type, higher nitrogen efficient type and nitrogen efficient type. Wuyunjing 27, Zhongdao 1, Ning No. 4, 7 to yield even japonica varieties nitrogen efficiency.