Comparison Of Yield And Mechanical Harvest Charactersof Summer Maize Under Different Cultivation Patterns

In order to clarify the suitable summer maize cultivation pattern in Dongting Lake region,and provide scientific support for high yield and high efficiency cultivation of machine-harvested summer maize,field experiments were carried out in Mutangyuan Town,Taoyuan County,Hunan Province from 2019 to 2020 with Zhengdan 958 and Xiangnongyu No.27 as materials.From the planting density,fertilizer application rate and chemical regulation,six different cultivation patterns were designed(high density,highnitrogen and chemical control,T1;high density,medium nitrogen and chemical control,T2;high density,low nitrogen and chemical control,T3;medium density,high nitrogen and chemical control,T4;medium density,medium nitrogen and chemical control,T5;medium density,low nitrogen and chemical control,T6),and the yield characters and harvest characters of summer maize under different patterns were comparatively studied with low density,high nitrogen and no chemical control pattern(CK)as the control.The main research results are as follows:(1)The yield of Zhengdan 958 and Xiangnongyu No.27 was higher in T2 and T1 patterns,and the yield of other patterns was lower than that of CK.The grain number in row,grain number per panicle and 1000-grain weight of two varieties under all patterns were lower than those of CK.The difference in yield between two varieties was clear,and yield of Zhengdan 958 was higher than that of Xiangnongyu No.27 under all cultivation patterns.(2)Cultivation pattern affected plant height and stem strength of summer maize.Plant height and stem diameter in each pattern of the two varieties were lower than that of CK.The puncture strength,compression breaking strength and tensile force were decreased with the increment of planting density and increased with the increment of nitrogen rate,so medium and high density coordinated medium and high nitrogen rate was advantageous to improve lodging resistance.The puncture strength,compression breaking strength and tensile force existed no clear difference between two varieties.(3)Cultivation pattern significantly affected the grain dehydration rate.The grain dehydration rate of both cultivars under T2 pattern was significantly higher than that under other patterns,and the grain dehydration rate under T5 pattern was the lowest.The grain dehydration rate existed clear annual difference,which showed weather conditions significantly affected the grain dehydration rate.(4)In 2019,at 55 d after silking,the water content ingrainsof Zhengdan 958 and Xiangnongyu No.27 ranged from 27.15%-29.10% and 31.73%-33.22%,respectively.In 2020,after 50 d of silking,there was more rain,and the grain water content decreased slowly,and the grain water content of the two varieties was between 32.25%-36.27% and35.45%-38.49%,respectively.It could be seen that under normal conditions,the suitable harvest time of Zhengdan 958 was 55 d after sillking,while that of Xiangnongyu No.27 was a little later.Comprehensively considering the yield,lodging resistance and grain dehydration rate,the high density,medium nitrogen and chemical control pattern(T2)was an ideal cultivation pattern in Dongting Lake region,which could obtain higher yield,faster dehydration in the later stage and shorter stem standing time in field.Relatively speaking,Zhengdan 958 was more suitable to be planted as summer maize variety in Dongting Lake area.