Effects Of Different Sowing Dates And Densities On Growth Characteristics And Yield Components Of Winter Wheat Under Drip Irrigation In South Xinjiang

In order to find the best sowing date and suitable density combination,to explore the density effect of different sowing time and the range of suitable density,this paper adopted Xindong 22（less-spike type）and Handan 5316（multi-spike type）widely promoted in southern Xinjiang.)For the test materials,the field test design of the split area is adopted.The main area is three sowing periods:September 23（B1）,October 4（B2）and October 15（B3）;the auxiliary area is four Seeding amount:3.15×10⁶grains/hm²（M1）,5.1×10⁶ grains/hm²（M2）,7.05×10⁶ grains/hm²（M3）and 9×10⁶ grains/hm²（M4）,observe different sowing under drip irrigation In terms of growth period,density and above-ground growth index,material accumulation and photosynthesis physiological index,nitrogen utilization index,grain filling characteristics and yield formation of wheat,the effects of different sowing date and density on the growth characteristics and yield composition of winter wheat in drip irrigation in southern Xinjiang The following conclusions are drawn:（1）The sowing period significantly affects the growth process of winter wheat under drip irrigation.As the growth period advances,the difference in the growth stage of the late sowing treatment becomes smaller,showing a certain growth compensation effect.Density has little effect on the fertility process.（2）The plant height of winter wheat in drip irrigation grows fastest at jointing-yanghua,and reaches the maximum in the middle of grain filling.The plant height increased with the increase of density and decreased with the delay of the sowing period.The plant height of Handan 5316 is more sensitive to density response.（3）With the increase of density,the height of the internodes and the center of gravity of the winter wheat base under drip irrigation increased,and the base diameter,mechanical strength and lodging resistance index decreased;with the delay of the sowing period,the internodes of the stalk base became shorter,the center of gravity height decreased,the diameter increased,the mechanical The intensity increases and the lodging resistance index increases.The effect of density on stalk traits is greater than the sowing date.In actual production,give full play to the interaction effect of density and sowing date,appropriately postpone sowing date and increase density,can optimize plant height and group individual growth,and ensure the formation of high yield.（4）The group size increases with the increase of density and decreases with the delay of the sowing period.The green leaf area per plant reaches the maximum at the flowering stage,and the population LAI is the highest at the booting stage,and decreases with the increase of density and the delay of the seeding period.This effect decreases with the growth process,that is,the late-sown winter wheat group has Better compensation and adjustment ability;the population size and leaf area dynamics of B2 and M2 or M3treatments change minimally with the growth process,and perform better leaf adjustment function.The sensitivity of the population size of Xindong 22 to the density and the sensitivity of the leaf area dynamics to the sowing date are both greater than that of Handan 5316,indicating that increasing the density and increasing the sowing volume has a greater impact on the population and canopy of large spike varieties,and should be paid attention to in production The sowing date should be adjusted under the premise of reasonable density and the multi-spike varieties should focus on adjusting the sowing amount under the premise of appropriate sowing date to obtain high yield.（6）The flag leaf Pn,Tr and Gs of drip irrigation winter wheat were the largest in the flowering period and the Ci was the smallest.The average Pn of Xindong 22 was in the B2 sowing period and Handan 5316was in the M3 sowing period.The Pn of B2M2 treatment was the highest,Xindong 22 and Handan 5316reached 15.45μmolCO₂/（m²·s）and 16.94μmolCO₂/（m²·s）respectively;Tr treated with M2 was the largest and treated with M4 was the smallest,with the delay of the sowing period,Tr was slowly rising The trend is the highest with B2M2（Xindong 22）or B2M1（Handan 5316）,respectively 6.35μmolCO₂/（m²·s）and6.08μmolCO₂/（m²·s）.The characteristic value of flag leaf photosynthesis in Handan 5316 was higher than that of Xindong 22,showing variety differences.（7）The flag leaf SPAD increased first and then decreased with the growth process,reaching the maximum at the flowering stage,and the highest treatment with B2M2,Xindong 22 and Handan 5316were 50.81 and 51.67,respectively.Both flag leaf SPAD decreased with increasing density.It decreases with the delay of the sowing period before flowering,and decreases with the delay of the sowing period after flowering.（8）The dry matter accumulation rate of winter wheat in drip irrigation is the largest at the jointing-booting stage,with the increase in density and the delay of the sowing date,the dry matter accumulation amount shows a downward trend,and it is more affected by Handan 5316;the increase in density significantly affects the grain dry matter,suitable Seed sowing（B2）has the largest accumulation of dry matter in grains,reaching 2.23².36 g/plant;the economic coefficient of each plant increases with the increase of density and the delay of sowing date.The dry matter TA,TR,CR and high density of pre-flowering organs of late planting After the anthesis,the input of dry matter to the grain has increased,indicating that under the conditions of late sowing,the economic efficiency of crop production can be improved by increasing the density.This effect is more pronounced in the few-spike varieties.（10）Nitrogen content of various organs of winter wheat under drip irrigation showed leaf>stem sheath>cob+spike hull before flowering,and grain>stem sheath>leaf>cob+spike hull at wax maturity,vegetative organ nitrogen before flowering The contribution rate of element translocation to grains was significantly higher than that of nitrogen accumulation after anthesis to grains.The sowing time is delayed,the nitrogen content of each organ decreases,the nitrogen content of each organ in the high-density treatment in the late sowing and the contribution rate of the nutrient organs before flowering to the grain is higher than that in the early sowing and low density,and the late sowing high density is conducive to the nitrogen of each organ after anthesis The accumulated amount is transported to the grain.（11）The grain filling rate of winter wheat under drip irrigation showed a bimodal change trend.The M2 and M3 treatments were the largest.The later the sowing date,the later the number of days for each treatment to reach the maximum grain filling rate.The rapid growth period of B2 treatment lasts longer,and its proportion of the maximum dry matter weight is higher than other sowing periods,reaching 59.98%⁷0.15%.（12）The sowing date was postponed,the number of spikes per plant,harvested ears and 1000-grain weight decreased,the number of spikes per ear of M2 and M3 increased;density increased,the number of spikes per plant,the number of spikes per ear and the weight of 1000-grain decreased,and the number of harvested ears increased.Among the combined treatments,the B2M3 treatment of Xindong 22 and the B2M2 treatment of Handan 5316 had the largest output,reaching 8548.43 kg/hm² and 9 222.81 kg/hm²,respectively.By simulating the relationship model of sowing date,sowing quantity and yield,we can see that Xindong 22 was sown on October 1 and the sowing quantity was 315.30 kg/hm²,and Handan 5316was sowing on October 2 with the highest yield of 262.47 kg/hm².Respectively reached 8 281.88 kg/hm² and 9 116.19 kg/hm²,and put forward the individual development index of the group under high yield conditions.