Regulation Effect Of Sowing Date Density On Winter Wheat Yield Formation In Eastern Hebei Province

The control of sowing date and density is one of the important factors to realize high yield cultivation of wheat.To clarify the effects of sowing date and density on wheat yield formation provides technical support for selection of suitable sowing date density combination and efficient utilization of natural resources in eastern Hebei province.In this study,Zhongmai 175 was used as the experimental material in two wheat growing seasons from 2019 to 2021,with three sowing dates of September 25(A1),October 5(A2)and October 15(A3)as the main area and the density as the secondary area.There were 2.62 million plants/hm~2(B1),3.75 million plants/hm~2(B2),4.87 million plants/hm~2(B3),6 million plants/hm~2(B4)and 7.12 million plants/hm~2(B5).To investigate the effects of sowing date and density on canopy light interception,chlorophyll content of flag leaf,tillering and panicle formation of individual plant,tiller dynamics of population,dry matter accumulation,yield and yield composition of wheat.The test results are as follows:1.The plant height of late sowing wheat was shorter;The canopy light interception increased with the growth period,and was in line with the vertical distribution of upper>middle>lower layers.The canopy light interception was low when the density was 2.62 million plants/hm~2and 7.12 million plants/hm~2,which was not conducive to the canopy light interception,but the transmittance was opposite.The chlorophyll content of flag leaves decreased with the advance of growth stage,and the chlorophyll content was higher under late sowing and low density treatment.2.The ear-bearing rate per plant,tiller capacity per plant and tiller panicle per plant decreased with sowing date and increasing density,while the main stem panicle increased with sowing date and increasing density.With the passage of sowing date,the time when the total stem number reached the maximum was delayed,and the total stem number decreased,but the total stem number increased with the increase of density.Tiller number and dry matter accumulation of wheat decreased with the advance of growth stage,and the difference of density increased after heading stage.Tiller number and dry matter accumulation decreased with the increase of density in the later growth stage,and decreased with the advance of sowing stage,and A1B1treatment was the largest at maturity stage.3.Total dry matter accumulation in shoot decreased with sowing date;Late sowing was not conducive to the development of spike traits in wheat,with lower grain number per spike and the lowest effective spike number under A3B1 treatment.The yield of late sowing wheat was lower,with the lowest treatment A3B1 and the highest yield of A1B1.The yield and yield components of the two years were different due to climate and rust disease,but the yield was higher under low density and early sowing and conventional sowing.In conclusion,the optimal sowing time for winter wheat in eastern Hebei is From September 26 to October 6.When sowing on September 26,the optimal density should be 2.62 million plants/hm~2,when sowing on October 6,the optimal density should be 2.62 million plants/hm~2,and if sowing on October 15,the optimal density should be 6-7.12 million plants/hm~2.