Effects Of Nitrogen Spike Fertilizer Application Period On Rice Growth And Yield And Rice Quality

In this study,Jigeng88?early maturity Variety,main stem leaf number 14?,Shennong265?medium mature variety,main stem leaf number 15?,Shennong1401?late maturing variety,main stem leaf number 16?and Beigeng1501?late maturing variety,main stem leaf number 16?was used as experimental material.Under the condition of local conventional nitrogen application?225kg/hm2?,adopt local conventional fertilization mode?base fertilizer,tillering fertilizer,and panicle fertilizer,bation of base-tillerig fertilizer:era-grain fertilizer=6:4?,We set with blank treatment?CK,no nitrogen application?and 4 different combinations of panicle fertilizer nitrogen application at leaf age in four varieties.According to the dynamics of leaf age,the precise application of flower-promoting fertilizer and flower-proteceing fertilizer are used in pairs to form different combinations of spike fertilizers with precise nitrogen application.Based on the leaf age process,this experiment selected four varieties of japonica rice with different numbers of main stem leaves.Based on years of research by the research team,the different analysis of the promotion of spikelet-promoting fertilizer and spikelet-protecting fertilizer at the leaf age stage were performed.Observe the stem pan dynamics,yield components,and dry matter accumulation of different panicle fertilizer combinations,and determine the appropriate panicle fertilizer application period for japonica rice varieties that do not require main stem leaves.precise application of flower promoting fertilizer and flower keeping fertilizer according to leaf age dynamics,to find the best application period of panicle fertilizer for Northern Japonica Rice.The result shows: 1.Yield and its constituent factorsThe four tested varieties all achieved the highest yield under the " inverted 4^th leaf + inverted 1^st leaf" ear fertilizer operation mode.The main reason for the high yield was the increase in effective ears and grains per ear,and the seed setting rate and thousand-grain weight were not low level.The test results show that the role of spikelet-protecting fertilizer is not only to promote flower retention,but also to increase the effective ear number,because in the inverted 5^th leaf or inverted 4^th leaf stage,it is the stage of young spike differentiation of rice.Gradually shifted from vegetative growth to reproductive growth,and the application of nitrogen fertilizer during this period can ensure that vegetative growth proceeds normally,reduce the death of young crickets,thereby increasing the number of effective tillers,and ultimately achieve high yield.Different ear fertilizer leaf age combinations had significant effects on the number of differentiated spikelets of Jigeng 88,Shennong 265,Shennong 1401 and Beigeng 1501.Nitrogen fertilizer application at inverted 4^th leaf better than inverted 5^th leaf,it leads to an increase in the number of differentiated spikelets.However,the number of spikelets degenerated less in inverted 1^st leaf,it can reduce the degeneration of spikelets.Therefore,the best application period of promoting flower fertilizer in Northern Japonica Rice is inverted 4^th leaf better than inverted 5^th leaf and the best application period of flower keeping fertilizer is that inverted 1^st leaf is better than inverted 2^nd leaf.Four varieties under the mode of "inverted 4^th leaf + inverted 1^st leaf" 1ncrease the number of solid grains,achieve the effect of increasing production.2.Physiological characteristics in critical periodsDuring the whole fertility process,the SPAD changes of the four varieties were basically consistent.The test results show that under the mode of "inverted 4^th leaf + inverted 1^st leaf" panicle fertilizer application,rice functional leaf SPAD decreases less in late growth,it shows that the post-fertilization can increase SPAD in the later growing stage,and have strong photosynthesis in the later stage.The activities of nitrate reductase and glutamine synthetase were positively correlated with nitrogen metabolism ability.Compared with inverted 2^nd leaf,the application of nitrogen in the first leaf significantly increased the activities of nitrate reductase and glutamine synthetase during the filling stage,indicating a delay.The application of flower-preserving fertilizer is conducive to the maintenance of these two enzyme activities,so that it can obtain higher nitrogen metabolism capacity in the remaining period.3.Material accumulation and transferWith the progress of the fertility process,the four tested varieties showed the same dynamic of dry matter accumulation in each growth period.Under the mode of "inverted 4^th leaf + inverted 1^st leaf" that mature period aboveground dry matter obviously increase.Compared with inverted 2^nd leaf nitrogen application,compared with inverted 1^st leaf,the biomass of ear was increased.The reason may be that the delay of fertilizer can prolong the time of grain filling and make the grain filling more sufficient.4.In terms of nitrogen absorption and conversion efficiencyThere were differences between the four tested varieties under different nitrogen treatments for ear fertilizer and nitrogen treatment and conversion efficiency after each treatment.In field production,nitrogen fertilizer utilization can be used to improve nitrogen fertilizer utilization efficiency.Uder the mode of "inverted 4^th leaf + inverted 1^st leaf" that it can effectively improve the recovery efficiency,physiological efficiency,partial factor productivity of applied fertilizer and nitrogen uptake efficiency by plant,conducive to nitrogen accumulation.5.Effects of nitrogen in panicle fertilizer on rice qualityThe effect of nitrogen on different qualities of rice is very complex,the research on rice quality in recent years has also become a research hotspot.The test results show that rice quality is affected not only by its own genetic factors,but also by external factors.This study shows that "inverted 5^th leaf + inverted 1^st leaf" is beneficial to increase the milled rice rate and the head milled rice rate."inverted 4^th leaf + inverted 2^nd leaf" can effectively reduce the chalkiness and chalkiness of rice."inverted 4^th leaf + inverted 1^st leaf " can reduce the protein content and amylose content in the grains and increase the taste value.