长江中下游稻区粳型超级稻高产形成及氮素利用的研究

选用长江中下游稻区7个粳型超级稻为试验材料,以普通粳稻为对照,在大田条件下设置7个氮肥水平(N0、150、187.5、225、262.5、300、337.5 kg/hm2),研究不同氮肥条件下粳型超级稻高产形成及其氮素利用特性。结果表明,超级粳稻在300 kg/hm2条件下产量最高,普通粳稻在262.5 kg/hm2条件下产量最高。超级粳稻两年最高产量平均值较普通粳稻高8.50%。与普通粳稻相比,超级粳稻各生育时期茎蘖数消长平稳,最终成穗率高,平均达78.10%;拔节前叶面积指数和光合势较低,拔节后较高。超级粳稻拔节前干物质、氮素积累量与普通粳稻相当,而拔节至抽穗、抽穗至成熟阶段干物质和氮素积累量较普通粳稻分别高7.31%、6.55%和8.98%、9.66%;超级粳稻氮素表观利用率、农学利用率和生理利用率较普通粳稻分别高3.73%、11.63%和7.95%。超级粳稻较普通粳稻更耐肥,在高肥条件下增产优势明显,且对应的氮肥利用率也较高。

Research on the formation of high yield and the nitrogen use of japonica super rice in the middle and lower areas of the Yangtze River

Using ordinary japonica rice as control, seven super japonica rice cultivars from the middle and lower areas of the Yangtze River were selected to investigate the effects of different nitrogen application levels (0, 150.0, 187.5, 225.0, 262.5, 300.0, 337.5 kg/ha) on their yield formation and the characters of nitrogen utilization under field conditions. Results showed that the highest yield is obtained with super japonica rice at nitrogen application level of 300.0 kg/ha and ordinary japonica rice at 262.5 kg/ha. The highest average grain yields of the seven super japonica rice cultivars was 8.5% higher than that of the ordinary japonica rice. Compared with ordinary japonica rice, the number of stems and tillers of super japonica rice are stable with higher percentage of productive tillers. The leaf area index and photosynthetic potential of super japonica rice was relatively low before jointing stage, and increased significantly after jointing stage. The dry matter and nitrogen accumulations in super japonica rice are similar to that of ordinary japonica rice before jointing, but 7.31% and 6.55% higher at jointing-heading stage, 8.98% and 9.66% higher at heading-maturity stage, respectively. The nitrogen use efficiency in super japonica rice is 3.73%, 11.63% and 7.95% higher than the ordinary japonica rice, respectively, suggesting that super japonica rice is adapted to high nitrogen fertilizer rate, and has relatively high nitrogen use efficiency under high fertility condition.