Under The Condition Of Late S Owing The Effects Of Sowing Date And Planting Density On Wheat Yield Formation And Quality In Yanjiang Wheat Region

In the Yanjiang wheat area of Jiangsu,in recent years,the growing popularity of mechanized light-simplified rice cultivation methods based on small seedlings and direct seeding,as well as the wide cultivation of high-quality,high-yield and late-ripening japonica varieties,the rice harvest period has been significantly delayed,resulting in the delayed planting of large areas of wheat,so it is used In the past,the appropriate wheat sowing period could no longer meet the actual production needs of the Yanjiang wheat area.To this end,this study uses Yangmai 23,which is widely used in the Yanjiang wheat area(Zhenjiang,Jiangsu),as the material,sets 5 planting dates and 5 planting densities,and studies the yield formation and quality of wheat by each planting date,density and combination The impact of clarifying the different sowing dates(A1,November 6;A2,November 12;A3,November 18;A4,November 24;A5,November 30)and under density(B1,180 10,000/hm2;B2,2.4 million/hm2;B3,3 million/hm2;B4,3.6 million/hm2;B5,4.2 million/hm2)Characteristics of high-yield wheat formation,to explore the range of moderate late sowing period and its supporting seeding density,Provide a basis for large-area wheat production in Yanjiang wheat area.The main findings are as follows:(1)With the postponement of the sowing date,the yield and the number of spikes,number of grains per ear,and grain weight all showed a downward trend;every day after the date of sowing,the yield decreased by 144.2 kg/hm2,the number of ears decreased by 60,000/hm2,The number decreased by 0.33 grains and the weight of 1000 grains decreased by 0.25 g.Starting from the density(basic seedlings)of 1.8 million/hm2,with the increase of density,the yield per hectare increases first and then decreases.The density of 3 million/hm2 yields the highest,reaching 7039.9 kg/hm2.With the increase of density,the number of spikes per hectare showed a linear increasing trend,and the number of grains per spike and the weight of 1000 grains decreased linearly;for every additional 100,000 basic seedlings,the number of spikes increased by 45,000/hm2,the number of grains per spike decreased by 0.23,and the weight of 1000 grains decreased 0.08 g.With the delay of the sowing period,the number of stems and tillers in the jointing,heading and maturity groups decreased accordingly.The number of stems and tillers in each period of the first sowing period(November 6)was significantly higher than other sowing periods,and the difference reached a significant level.With the increase of density,the number of stems and tillers in jointing stage,heading stage and mature stage showed an increasing trend.The minimum sowing density(1.8 million/hm2 basic seedlings)of each stage was significantly lower than other density treatments,and the difference reached a significant level.With the postponement of the sowing period,the leaf area index of the wheat plant during the critical growth period decreased significantly.For each postponed sowing period,the leaf area index of jointing stage,booting stage,flowering period,and 20 days after flowering decreased by 0.49,0.80,0.68,0.47,respectively.With the increase of density,the leaf area index of wheat plant at critical growth period and the attenuation rate of leaf area from booting to 20 days after flowering increased significantly.Different sowing dates and density treatments have a significant effect on the material accumulation of wheat during the main growth period;with the delay of the sowing date,the material accumulation of the jointing,heading and maturity periods decreased significantly.For each delayed sowing date,the jointing and heading periods,The amount of material accumulation in the mature period decreased by 0.46,0.81,1.41 t/hm2,and the decline increased with the growth process.With the increase of density,the accumulation of material at the jointing stage,heading stage and mature stage showed the characteristics of increasing first and then decreasing,and the accumulation of the material at each growth stage was the highest with the treatment of 3 million/hm2.In this study,the suitable sowing date of Yangmai 23 is November 6,and the sowing volume is 3 million/hm2;after the late sowing,the density should be increased,preferably about 3 million/hm2,too low and too high are conducive to high yield.By increasing the sowing density,it can only compensate to a certain extent,but cannot completely compensate for the loss of production caused by the delay of the sowing date.(2)With the advancement of wheat growth process,the nitrogen content of the plant in each growth period of wheat showed a downward trend,and the total nitrogen uptake continued to increase.The nitrogen content and nitrogen absorption of plants in the key growth period of wheat showed a decline with the delay of the sowing period;the nitrogen content and nitrogen absorption of plants in the key growth period of wheat showed an increase first and then a decrease with the increase of planting density The trend is the largest under B3.Nitrogen accumulation between different treatments showed basically the same changes with the growth process,and all showed the accumulation dynamics of S-shaped curve.The accumulation from seeding to jointing period is relatively small,and the accumulation from jointing to flowering period accounts for the largest proportion in the whole growth period,and the nitrogen accumulation after flowering tends to be flat.Nitrogen accumulation in wheat from sowing to jointing,jointing to flowering,and flowering to maturity generally decreased with the delay of the sowing period;nitrogen accumulation from wheat sowing to jointing,jointing to flowering stage increased first with the increase of planting density The trend of the latter decrease is the highest under B3 treatment.With the progress of the fertility process,the changes in nitrogen absorption rate between different treatments were basically the same,and all showed a trend of increasing first and then decreasing.The specific performance is that the rate of nitrogen absorption from planting to jointing stage is the lowest,from jointing to flowering stage,the absorption rate is the highest,and the nitrogen absorption rate gradually decreases after anthesis.The rate of nitrogen accumulation in plants at all stages of sowing to jointing,jointing to flowering,and flowering to maturity showed a decline with the delay of the sowing date;with the increase of density,the trend was to increase first and then decrease.In terms of nitrogen utilization,as the sowing date is delayed,wheat partial nitrogen productivity,nitrogen demand per 100 kg of grain,and nitrogen absorption efficiency decrease accordingly;as planting density increases,wheat nitrogen partial productivity,nitrogen demand per 100 kg of grain,Nitrogen absorption efficiency showed a trend of increasing first and then decreasing,and the difference reached significant.There was no obvious change in the nitrogen harvest index.The results of this study show that the sowing date and density have significant effects on the nitrogen absorption and utilization of wheat plants.Delaying the sowing date significantly reduces the nitrogen content,nitrogen absorption and nitrogen accumulation of wheat at various stages,which is not conducive to wheat nitrogen.Element accumulation.Increasing the seeding density can improve the nitrogen utilization efficiency of wheat to a certain extent,but it cannot compensate for the effect caused by the late sowing date.A suitable combination of sowing date and sowing density is conducive to improving nitrogen absorption and utilization of wheat plants(3)Sowing date and density have a significant effect on the quality of wheat grain processing.With the delay of the sowing period,the grain hardness,bulk density and flour yield rate showed a decreasing trend,and the difference in hardness and flour yield reached a significant level,but the bulk density difference was not significant;the drop value showed an upward trend and the difference reached a significant level.With the increase of density,the flour yield,grain hardness and bulk density increase,and the drop value shows a downward trend,and the difference reaches a significant level.With the delay of the sowing period,the content of grain protein,dry gluten and wet gluten decreased between treatments,and the difference was significant.During the same sowing period,with the increase of sowing density,the grain protein,dry and wet gluten content showed a trend of increasing first,and showed that the protein content and gluten content of low-density treatment were significantly lower than that of high-density treatment.Under the same density treatment,the peak viscosity,trough viscosity,final viscosity and rebound value all showed a significantly increasing trend with the delay of the sowing period.The slack value increased first and then decreased with the delay of the broadcast period,and the difference reached a significant level.The gelatinization characteristics of wheat starch treated with different seeding densities in the same sowing date specifically show that with the increase in seeding density,the peak viscosity,trough viscosity and final viscosity of wheat starch in each sowing period showed an increasing trend,all of which reached significance.Difference level.With the increase of density,the lean value of wheat showed a trend of decreasing first and then increasing.The rebound value of wheat is less affected by density,and the difference is not significant.The difference in the gelatinization temperature of wheat starch between sowing date and density treatment is not obvious,and the performance is generally stable.With the delay of the sowing period,the water absorption rate,dough formation time,dough stability time and evaluation value were significantly reduced,and the difference reached a significant level.Postponing the broadcast period,the weakening degree showed an upward trend,and the difference reached a significant level.During the same sowing period,with the increase of sowing density,the water absorption rate of wheat,dough formation time,dough stability time gradually decreased,the difference reached a significant level.Increasing the seeding density,the degree of weakening first decreases and then increases,and the evaluation value first increases and then decreases.The results of this study show that early seeding period is beneficial to the improvement of wheat grain processing quality;increasing the seeding density also has a certain effect on wheat grain processing quality.Properly delaying the sowing date and reducing the sowing density have a significant effect on the increase of the wheat drop value.