Effects Of Different Nitrogen Levels On Yield,quality And Nitrogen Use Efficiency Of Candidate Varieties In Green Super Rice

Rice is an important food crop.In order to pursue high yields,people once relied on the application of nitrogen fertilizer.With the continuous increase in the amount of nitrogen fertilizer application,the contradiction between agricultural development and resource and environment becomes more prominent.To change this situation,ultra high yield and drought resistance are needed.The concept of green super rice,which is resistant to disease and high-efficiency nitrogen fertilizer,provides new ideas for breeding and production.The proposal and practice of green super rice promotes the sustainable development of agriculture.Based on the concept of green super rice,this study analyzed the differences in yield,nitrogen use efficiency,and rice quality of different rice varieties under different nitrogen application rates.Through comparison,the varieties that met the criteria of green super rice were selected.The main results are as follows:1.The yields of rice varieties were highest when nitrogen fertilizer was applied at 15 kg/667m2 and 18 kg/667m2,respectively.The rice yields of both V2 and CK2 increased with the increase of nitrogen application rate,and V1,V3,V4 and CK1 were four kinds of rice.The yield began to increase with the increase of nitrogen application rate.When the nitrogen fertilizer application reached a certain amount,the nitrogen application amount was increased and rice yield began to decline.When the nitrogen application rate of all varieties exceeded 10 kg/667 m2,the increasing trend of the yield was slowed down.The number of grains per spike was greatly affected by the amount of nitrogen applied,and the effect of yield increase was significant.The highest yield among the six varieties was Jingliangyouhuazhan,which reached 588.99 kg/667m2,which was 11.13%higher than that of the control variety Yongyou 2640 and 14.35%higher than Shanyou 63.2.With the increase of nitrogen application rate,the SPAD values of all varieties increased,and along with the progress of childbearing,the change trends of different nitrogen levels of all varieties were the same,and there were "black and yellow"changes.In the main growth stages,the SPAD value of rice leaves showed the tillering stage>heading stage>mature stage.3.The amount of nitrogen applied increased the nitrogen content of various organs of rice plants,and there was a certain difference between the treatments of nitrogen fertilizer.There was no significant difference among the varieties.The nitrogen content of stems,sheaths and leaves in the tiller stage was higher than that at the heading stage,and the leaf nitrogen content of the rice plants at the tillering and heading stages was higher than the stem nitrogen content.At maturity stage,the nitrogen content of each organ of rice in each variety showed grain>branch>straw.4.Within a certain range,the nitrogen agronomic efficiency first increased and then decreased with the increase of nitrogen application rate.All varieties were highest under N2(8 kg/667m2)treatment,they were 20.65 kg/kg,22.79 kg/kg,23.01 kg/Kg,24.31 kg/kg,15.97 kg/kg,and 13.21 kg/kg,there is a certain difference between different nitrogen treatments,the significant degree varies with different varieties.Among the varieties,Quanyou683>E Liangyou 476>Jingyouyouhuazhan>Huiliangyou 858>Yongyou 2640>Shanyou 63.The partial nitrogen productivity gradually decreased with the increase of nitrogen application rate,and the highest was in the range of 60-71 kg/kg,and the lowest was in the range of 30-36 kg/kg.Among the nitrogen partial productivity varieties,Jingyouliangyouhuazhan>Quanyou 683>Huiliangyou 858>Eliangyou 476>Yongyou 2640>Shanyou 63.5.Roughness,polished rice rate,polished rice rate,rice aspect ratio,and protein content all increased gradually with the increase of nitrogen application rate.Rice grain size became smaller,milling quality and nutritional quality were improved,chalky traits The trend of change is related to its variety.Jingliangyouhua accounted for a good overall milling quality,large grain size,excellent chalky traits,and highest rice protein content.