Effect Of Precise Leaf Age Fertilization On Rice Yield And Nitrogen Utilization Rate

Nitrogen fertilizer is one of the nutrient elements required for rice growth and development,and plays an important role in rice growth and development and yield formation.At present,the excessive use of nitrogen fertilizer in China has caused many problems.Rational application of nitrogen fertilizer is particularly important,and optimizing the operation mode of nitrogen fertilizer is one of the important measures to improve rice yield and nitrogen utilization rate.On the basis of total nitrogen application of225kg hm^-2 and light simple fertilization?basal fertilizer,tiller fertilizer and panicle fertilizer?,Northeast typical super japonica rice varieties with different main stem leaves were selected,Jigeng 88?main stem leaves 14?,Shennong 265?main stem leaves 15?,Shennong 1401?main stem leaves 16?and Beigeng 1501?main stem leaves 16?was used as the test material,According to the combination of different leaf ages,the experiment of precise nitrogen application of tiller fertilizer and ear fertilizer was carried out.The effects of different nitrogen fertilizer patterns on morphological indexes,population characteristics,yield,nitrogen absorption and utilization of rice were studied in 2018²019.Main research results:?1?The effects of different tillering and panicle nitrogen treatments on the growth dynamics of intervarietal leaf age,main stem leaf number and plant height were not significant,but the rice tiller yield was significantly affected.Compared with conventional fertilization,The backward shift of tiller fertilization time significantly increased the ear formation rate of different rice varieties,That is,Jigeng 88 increased by 11%,Shennong265 increased by 10%,and Shennong 1401?Beigeng 1501?increased by 7%¹2%,The results showed that the application period of tillering fertilizer was appropriately shifted back,which had the effect of promoting and preserving tillering.?2?Different nitrogen fertilizer treatments showed different differences in photosynthetic traits.There was a higher and suitable LAI after the earing stage when the tiller fertilizer application period was moved back;The chlorophyll content increased by7%¹7%from the ear stage to the filling stage;After the full heading period,rice gradually senesced,but shifting the application time of tillering fertilizer can slow down the senescence of leaves;The net photosynthetic rate and Rubisco enzyme activity of booting stage and grain filling stage of rice increased significantly by 10.7%and 11.4%,respectively.The results showed that the application time of tiller fertilizer delayed the senescence of leaves,increased the photosynthetic characteristics of rice in the middle and late stages,and increased the yield of crops.?3?Under different nitrogen application models,the dry matter accumulation of rice was significantly higher from booting stage to maturity stage when tiller application time moved backward.The later application time of tillering fertilizer also has certain influence on the dry matter accumulation of each organ in different growth stages.From tillering stage to heading stage,the time of tillering and fertilization moved backward,the accumulation of stem and sheath increased about 15.0%,and the accumulation of dry matter in leaves increased about 23.0%.After booting stage,there was no significant difference among treatments.In the accumulation of panicle,there was no significant difference between booting stage and grouting stage.From the filling stage to the maturity stage,the tiller fertilizer application time was significantly increased by about 29% by moving backward.The population growth rate of rice is about 18.6% higher during the tillering stage to booting stage,when the application time of tiller fertilizer is moved backward.?4?Different leaf age combinations had significant effects on nitrogen metabolism related enzymes and nitrogen utilization.During booting and filling stages,the NR and GS enzymatic activities were increased by 30.3%and 22.3%,respectively,when the application time of nitrogen fertilizer moved backwards.The backward application time of tillering fertilizer can increase the total nitrogen accumulation of the plant by 9.0%to 17.2%,The utilization rate of nitrogen absorption increased by about 26.1%,the agricultural utilization rate also increased significantly,the physiological utilization rate increased by about 32.2%,and the partial productivity was 14.4%to 29.8%higher than that of conventional treatment;There was no significant difference in nitrogen accumulation in rice tillering stage with backward movement of tillering fertilizer application time,but it was significantly higher in tillering stage to booting stage than in conventional treatment 9%¹7.2%.?5?The application time of tiller fertilizer moved backward significantly increased rice yield,Jigeng 88 increased by 16.4%²1.8%,Shennong 265 increased by about 16.5%,shennong1401?Beigeng 1501?increased by about 26.5%.Among the yield components,the effective panicle number of rice with tiller fertilizer application time moving backward was about 19.5%higher than that of conventional treatment,and the grain number per panicle of the three varieties was 9.2%¹7.3%higher.The model of nitrogen fertilizer had a certain effect on the ear characters of rice,but had no significant effect on the primary branch and stem,In terms of secondary branches,the main manifestation was that tiller application time moving backward could significantly increase the number of branches and grains.The results of correlation analysis showed that the number of secondary branches and the number of secondary branches were positively correlated with the yield.In summary,we believe that reasonable optimization of tillering fertilizer application period can be conducive to the improvement of tiller number and tiller yield of rice,Increase the photosynthetic characteristics in the late growth stage,improve the activities of enzymes related to nitrogen metabolism in 0the middle and late stages of rice,and promote the absorption and utilization of nitrogen in rice,thus increasing the yield of rice.