提高超级杂交稻库容量的施氮数量和时期运筹

【目的】探索提高超级杂交稻库容量的氮素优化措施,对于提高氮肥利用效率和实现超级杂交稻养分高产高效具有重要现实意义。【方法】以具有代表性的超级杂交稻品种Y两优1号为材料,通过不同氮素施用量(基、穗施氮比例80﹕20下施氮量为0-270kg.hm-2)与施用时期运筹(施氮量180kg.hm-2下基、蘖、穗、粒不同施氮比例)的田间试验结合水稻主要生长性状调查和数学回归方法,分析构建超级稻最大库容量的指标及其氮素优化措施。【结果】施氮量与超级杂交稻有效分蘖(穗)线性相关,与穗实粒数、总实粒数和产量二次抛物线相关;基、穗施氮比例80﹕20条件下超级杂交稻施氮量为215.6kg.hm-2时,单位面积总实粒数最大;施氮量为245.9kg.hm-2时,产量达到最高(11.42t.hm-2)。基、穗两时期施氮比例为60﹕40,以及进一步分配为基、蘖、穗、粒施氮比例10﹕50﹕25﹕15时,超级杂交稻的穗实粒数、总实粒数和产量显著增加,在减少施氮65.9kg.hm-2基础上,可分别比基-穗施氮比例80﹕20条件下,施氮-产量模拟方程求得的最高产量增加2.01%、2.89%。【结论】通过减少基肥氮比例、增加蘖肥氮和穗粒肥氮比例等氮后移的优化措施,可提高分蘖数、增加成穗率和穗实粒数,从而显著提高最大库容量(总实粒数)和产量,充分发挥品种的产量潜力,并有效减少施氮量。

A Preliminary Study on Optimizing Nitrogen Fertilization Amount at Different Phases to Enhance the Storage Capacity of Super Hybrid Rice

Objective]Study on optimization of nitrogen fertilization to raise the storage capacity of super hybrid rice has significant practical importance on the improvement of nitrogen-fertilizer utilization efficiency and realization of high-efficiency of fertilizer and high-yield of super hybrid rice. Method]The experimental material is Y Liangyou No.1 which is a representative super hybrid rice.By fertilizing different amounts of nitrogen at different phases (different nitrogen amounts as the ratio of base-spike was 80 to 20 and different ratio of base-tiller-spike-grain nitrogen as the total nitrogen was 180 kg·hm~(-2)),along with the investigation of characters of rice during growth and the use of mathematical regression,the index of maximum storage capacity and the measures to optimize the nitrogen utilization were analyzed. Result]The nitrogen application amount had linear correlation with available tillers (spikes),and second-degree parabola correlation with filled grains per spike,total filled grains and yield per area;With the base-spike nitrogen-fertilizer application ratio was 80 to 20,when the nitrogen application amount was up to 215.6 kg·hm~(-2),total filled grains reached the maximum.When the nitrogen application was up to 245.9 kg·hm~(-2),the yield reached the highest (11.42 t·hm~(-2)).When the base-spike nitrogen application ratio turned to 60 to 40,and further base-tiller-spike-grain nitrogen application ratio was adjusted to 10:50:25:15,the filled grains per spike,total filled grains and yields of super hybrid rice remarkably increased,the yeilds increased by 21% and 2.89% respectively,compared with the highest yields calculated by simulated equation of yield - nitrogen application when the nitrogen application amount decreased by 65.9 kg·hm~(-2),when the base-spike nitrogen ratio was 80 to 20. Conclusion]By nitrogen application optimization measures like reducing base nitrogen ratio,increasing the ratios of filler nitrogen,spike and grain nitrogen,the effective tillers,spike rate and filled grains per spike would increased,therefore,the maximum storage capacity and yield of super hybrid rice would largely increased,the yield potential of hybrid rice would be fully developed and the nitrogen application amount could be reduced effectively.