| Grain filling is the key physiological process of forming corn grain yield,the increase of planting density is one of the main ways to improve corn yield,improve soil fertility can effectively alleviate the adverse effects of dense planting conditions on maize single plant,and then regulate the growth and development of plants under high density conditions and promote grain dry matter accumulation.In order to explore the regulation mechanism of different soil fertility on maize grain filling,the influence and mechanism of soil fertilization on different varieties of grain filling were revealed from the perspectives of canopy photosynthetic properties,grain filling characteristics,yield and composition,and grain nutritional quality under the tillage mode of different densities,medium,medium and low soil fertility.The results of the study provide a theoretical basis for increasing maize yield.The main results are as follows:(1)Increase soil fertility,increase the average grouting rate,increase the ultimate growth of the grain,delay the time when the maximum grouting rate is reached,increase the grain growth rate when the grouting rate is maximum,prolong the active grouting period,and increase the maximum grouting rate,with the increase of planting density,on the basis of improving soil fertility,the average grouting rate,the ultimate growth of the grain,the maximum time of the filling rate and the maximum grouting rate of the grouting rate are increased,which reduces the growth amplitude of low soil fertility.(2)Increasing soil fertility can increase the effective panicle number caused by the densification process,reduce the number of panicles and the decrease in 100 grain weight caused by densification,thereby increasing the yield of maize grains,and the best two years of high soil fertility performance increased by 7.22%-10.29% and 9.39%-10.44%compared with CK,respectively.With the increase of planting density,the increase in maize yield increases on the basis of increasing soil fertility.Among them,the yield increase effect of high soil fertility was the most significant,and the highest yield was obtained under the condition of high density 112500 plants/ha,which was increased by1.43-2.29 t/ha compared with CK,respectively.(3)The soil fertility was enhanced,and the bulk density of maize grains,the total starch content of grains at each stage,the crude fat content of grains at each stage,the crude protein content in S1 and S2 periods,and the soluble sugar content in S1 period increased significantly.The content of soluble sugars in S2 and S3 stages and crude protein content in S3 stages was reduced.With the increase of planting density,on the basis of improving soil fertility,the growth rate of corn grain starch content,S3 grain crude fat content and S1 period crude protein content in each period was increased,and the content of soluble sugars in S2 and S3 stages and the crude protein content in S3 stage were increased.(4)Improving soil fertility can alleviate the decline in leaf photosynthetic properties caused by the advancement of the growth process,delay leaf aging,and prolong the canopy photosynthetic time,among which the high soil fertility increases by14.78%-34.89%,3.27%-12.39%,5.55-8.69%,23.88-30.05% at the maturity stage compared with CK.The increase in planting density significantly reduced the photosynthetic properties of the canopy,but the decrease at high soil fertility levels was smaller than that of CK.Increasing soil fertility increased the accumulation and transport of dry matter per plant after flowering,which increased by 3.48%-16.75%,3.79%-12.35%compared with CK;increasing the density to 112500 plants/ha,improving soil fertility,increasing the accumulation and transfer rate of post-flowering single plants. |
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