Effects Of Plant Density And Nitrogen Application Rate On Yield Formation And Nitrogen Use Efficiency Of Autumn Maize

With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize was gradually increased,It needs to provide the theoretical basis and technical support for the high yield and high efficiency of autumn maize.In this study,semi-compact autumn maize cultivar Qinyu 58 was used as experimental material,The effects of nitrogen fertilizer,density and intercropping on the canopy structure,dry matter accumulation,distribution,transport,yield and yield of autumn maize were studied.The results showed that the nitrogen content was the main area and the planting density was the secondary area.Yield composition and nitrogen use efficiency.In this experiment,four treatments were carried out,including nitrogen application(N0),nitrogen 210 kg/ha(N210-1 for base fertilizer and topdressing),210 kg/ha nitrogen With topdressing 2 times,N210-2),nitrogen 300 kg/ha(base fertilizer 1 and top dressing twice,N300).A total of 60,000 plants/ha(D1)of 78,000 plants/ha(D2),high density of 93,000 plants/ha(D3)were planted.The main results show that: 1.Under the experimental conditions,the planting density and nitrogen application and their interaction had no significant effect on plant height,ear height and stem diameter.The effect of density and nitrogen application on the leaf area index of each period was significant,and increased with the increase of density.After nitrogen application,the increase of nitrogen application increased with the increase of nitrogen application rate.The influence of leaf area index was not significant.2.Under the experimental conditions,the planting density had a significant effect on the light transmittance at different levels after the large trumpet stage.With the increase of the density,the(middle or)ear layer and the bottom light transmittance showed a decreasing trend.The effect of nitrogen application on it was not significant,and the effect of density and nitrogen application was not significant.3.Under the experimental conditions,the effects of planting density and nitrogen application rate on the dry matter accumulation during the whole growth period were significantly higher than those of the control.The increase of nitrogen application rate increased with the increase of nitrogen application rate.The dry matter accumulation of the population was also increasing,but the effect of planting density and nitrogen application rate on the dry matter accumulation of each group was not significant.The effect of planting density and nitrogen application rate on the dry matter accumulation after anthesis was not significant.4.Under the experimental conditions,the effects of planting density and nitrogen application and their interactions on grain number per spike and grain weight were not significant.The difference of yield was mainly from spike number and high density(93000 plants/ha)significantly better than low density(60000 plants/ha),nitrogen fertilizer shift seems to have no effect on yield.There was no significant difference in the yield of medium density(78000 plants/ha)and high density(93000 plants/ha)under nitrogen treatment,except for N210-2 treatment.Therefore,in the middle and lower reaches of the Yangtze River area of autumn corn cultivation,the density is set to 78000 plants/ha,N210-1 nitrogen fertilizer treatment level can achieve higher yields.5.Compared with N210-1,medium density(78000 plants/ha)and high density(93000 plants/ha)N210-2 nitrogen fertilizer were significantly increased by nitrogen fertilizer use efficiency.The nitrogen recovery efficiency and the maximum accumulation of nitrogen in the mature stage were in the medium density(78000 plants/ha)under N210-1 treatment.Combined with yield data,the most suitable autumn maize high yield and nitrogen efficient use of the planting pattern was medium density(78000 plants/ha)under N210-1 treatment.