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 tiller 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.