不同生育时期氮肥减施对水稻群体生产特征的影响及减肥策略初步分析

Effects of nitrogen reduction at different growth stages on rice population production characteristics and preliminary analysis of nitrogen reduction strategies

以大面积应用的优质高产品种南粳5055为材料,设置常规施氮与5个不同生育时期减氮处理,分析氮肥减施对水稻群体生产特征及产量形成的影响。结果表明:集中于某个时期的减肥措施无法避免水稻群体生长量的大幅减少,产量显著下降,而均衡减氮处理有效穗与每穗粒数虽有所降低,但结实率显著提高,最终产量差异不显著或小幅下降。与常规施氮处理相比,均衡减氮处理成穗率大幅提升,在获得适宜群体颖花数的基础上提高结实率,维持较高的结实期绿叶面积,且结实期光合能力显著提升;抽穗后的物质积累量、茎鞘物质转运率显著提升,维持较高的结实期群体生长速率与净同化速率,表现出较优的物质生产与转运利用特征。各减氮处理同样降低氮素吸收和积累总量,但提高氮素利用效率。均衡减氮处理在结实后期表现出较高的氮素吸收速率与转运能力,氮素利用效率显著提升,表现出较好的资源利用与高效生产特性。

In this experiment,the high-yield and high-quality variety Nanjing 5055 is the supplied sample.Regular nitrogen application and nitrogen reduction in five different growth stages are planned to analyze the impact of nitrogen fertilizer reduction on rice production characteristics and yield formation.Results indicate:fertilizer reduction in a certain period failed to prevent the drastic decrease in output of the rice community amount.In comparison,although the equilibrium reduction of nitrogen showed a decrease in effective panicles and the number of grains per ear,the seed-setting ratio significantly increased,the final output did not show a drastic decline.Compared with regular nitrogen application,the equilibrium reduction of nitrogen ensured the increase in the rate of ear bearing tiller.Besides,top-three leaves were long and straight,photosynthetic capacity during the productive phase was also drastically improved.After earring,the equilibrium reduction of nitrogen indicated significant increase in dry matter accumulation,dry matter transport and the rate of contribution to ears,maintained a high growth rate and assimilation rate during the productive phase.In addition,it also enhanced the efficiency of dry matter production and transport in the middle and later periods of fructification and demonstrated favorable traits of dry matter production and transport.Nitrogen reduction lowered the total accumulation of nitrogen absorption,but it increased the rate of nitrogen utilization.In the later period of fructification,the equilibrium reduction of nitrogen showed a high rate of nitrogen absorption and transport.In comparison with regular nitrogen application,nitrogen utilization efficiency also increased apparently,showing positive traits of resource utilization and efficient production.