Effects Of Nitrogen Fertilizer Management On Yield,Quality And Lodging Resistance Of Japonica Rice Under Drill Seeding

In order to explore the growth characteristics,yield performance and rice quality of dryseeded rice under different nitrogen fertilizer management,four rice varieties suitable for direct seeding,Jinongda 878,Shendao 528,Shendao 529 and Yuanfeng 6.Under the nitrogen application level of 180kg/hm2,five nitrogen fertilizers were studied(the ratio of base fertilizer,tiller fertilizer and joint fertilizer is 0:7:3,5:5:0,3:5:2,0:5:5,4:2:4).Yield and yield components of various varieties,rice quality,dynamics of stem and stalk growth during the growth period,lodging characteristics,photosynthesis and chlorophyll index,leaf area index,dry matter accumulation and population growth.The yields of the four varieties showed that Yuanfeng 6 was higher than Shendao 528,and Shendao 529 was higher than Jiongda 878,which reached the highest and significantly higher than the other four treatments under N3(3:5:2)treatment.The best performance is Yuanfeng 6 N3 treatment is 11.67 t / hm2.With the increase of the proportion of nitrogen application in the early stage,the variation trend of the yield and effective panicle number of the four directseeded rice varieties was basically the same as increasing first and then decreasing.There was a large difference in the number of effective panicles per unit area of Shendao 528,and the highest was treated in N3.The yield and effective panicle number of each variety reached the maximum at the same time under different nitrogen fertilizer operations.The backward shift of nitrogen application rate in the early stage increased the rate of polished rice and whole milled rice in the direct-sown rice.With the shift of the proportion of nitrogen fertilizer,the chalkiness and chalkiness rate decreased first and then increased,while the protein content increased gradually and the maximum value was treated at N5(0:5:5).According to the RVA spectrum,as the proportion of nitrogen fertilizer moves backward,the peak viscosity of the four varieties gradually increases,and the final viscosity gradually decreases,while the protein content gradually increases.Therefore,the nitrogen fertilizer can be moved in an appropriate range to improve the rice taste quality.As the proportion of nitrogen fertilizer in the previous period decreased,the number of basic seedlings of the four varieties also decreased,and the time when the number of tillers reached the peak was continuously pushed back.The emergence rate of each variety was stable above 70%,and the rate of ear formation increased significantly with the treatment,reaching the maximum at N3.The leaf area index decreased with the proportion of the base fertilizer,and the leaf area index increased continuously.The treatment without the base fertilizer was slightly reduced.The light transmittance of Shendao 528 group was greatly affected by the treatment of nitrogen fertilizer.The effect of nitrogen fertilizer on the leaf area index increased the light transmittance of the group significantly,which affected the photosynthetic capacity of the plant.The dry matter accumulation of the stems of the four varieties decreased significantly with the decrease of the nitrogen rate in the previous period,and reached the maximum at N3.Except for Yuanfeng 6,the dry matter accumulation of various varieties in the treatment stage increased significantly with the nitrogen fertilizer migration.Appropriate reduction of the ratio of base fertilizer has the same effect on the growth rate of the population.Nitrogen fertilizer rearward significantly increased the nitrogen uptake capacity of rice,which was significantly higher than other treatments under N3(3:5:2)treatment.And putting all the nitrogen application rate in the later stage will not only cause a decrease in the total amount of nitrogen accumulation,but also reduce the nitrogen utilization rate.In the appropriate range,the nitrogen factor partial factor productivity increased significantly with the nitrogen fertilizer migration,indicating that the nitrogen fertilizer rearward movement can improve the nitrogen fertilizer utilization rate and the nitrogen application capacity of rice.With the shift of nitrogen ratio in the early stage,the changes of net photosynthetic rate of the four varieties were increased first and then decreased,and both were significantly higher at N3(3:5:2)than other treatments,four varieties.The transpiration rate was almost the same as the net photosynthetic rate.It indicated that proper pre-transfer rate of nitrogen in the early stage could significantly increase the net photosynthetic rate of rice flag leaves and improve the photosynthetic performance of rice.Among the four varieties,except for Shendao 529,the twisting force of the three sections of the other varieties was significantly higher at N4 than other treatments.With the increase of the proportion of nitrogen in the early stage,the lodging index increased.The smaller the lodging index between the nodes,the better the lodging resistance.The internode length of the four varieties under N1 treatment was significantly higher than other treatments,but the crosssectional area was also the lowest,which caused the mechanical strength of the stem to decrease,indicating that the proportion of nitrogen in the early stage increased the possibility of plant lodging.