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选用长江中下游地区有代表性的50个早熟晚粳品种(系),设置7个氮肥水平(0、150.0、187.5、225.0、262.5、300.0、337.5kghm2),得出各品种在各个氮肥水平下出现的最高生产力及其对应施氮水平,将该最高生产力定义为氮肥群体最高生产力。在此基础上,比较研究不同氮肥群体最高生产力水稻品种间氮素吸收利用的差异。结果表明,生产力处于顶层与高层水平品种的颖花量极显著高于中层、低层品种,颖花量的增加主要表现为每穗粒数的极显著增加。各生育阶段的植株吸氮量和氮素吸收速率均随着生产力等级的增加而显著增加。4个生产力等级品种间在移栽至拔节和拔节至抽穗阶段氮素积累比例差异均不大,但随着生产力等级的增加呈减小趋势;抽穗至成熟阶段氮素积累比例随着生产力等级的增加呈显著增加趋势,顶层水平品种在抽穗至成熟阶段氮素积累比例为14.94%。氮肥表观利用率、农学利用率和生理利用率均随着生产力等级的增加而增加。初步筛选出13个集高产与氮高效于一体的品种。
Fifty early-maturing late Japonica rice varieties (lines) were selected from the middle and lower reaches of the Yangtze River. Seven nitrogenous fertilizers (0,150.0,187.5,225.0,262.5,300.0,337.5kghm2) were set up. The highest productivity that occurred and its corresponding N application level defined this highest productivity as the highest productivity of the N application group. On this basis, the differences of nitrogen uptake and utilization among the highest productivity rice varieties with different nitrogenous fertilizer groups were comparatively studied. The results showed that the productivity of spikelets at the top and top levels was significantly higher than that at the middle and lower levels. The increase of spikelets was mainly due to the extremely significant increase of spikelets per spike. The nitrogen uptake and N uptake rate of plants in each growth stage increased significantly with the increase of productivity level. There was no significant difference in the percentage of nitrogen accumulation between the four cultivars with different productivity levels during transplanting and jointing to jointing stage and heading stage, but decreased with the increase of productivity level. The ratio of nitrogen accumulation from heading stage to mature stage varied with productivity level Increased significantly, and the nitrogen accumulation rate of the top-level cultivars from heading to maturity was 14.94%. Apparent utilization of nitrogen fertilizer, agricultural utilization and physiological utilization rate with the productivity level increases. Preliminary screening of 13 sets of high yield and nitrogen efficient in one of the varieties.