Effects Of Density And Drip Irrigation On Growth Characteristics Of Winter Wheat And Its Coordination Model

The experiment was conducted in the net room of Tarim University Agricultural Experiment Station from 2016 to 2017,with winter wheat as the research object.Test design was used in the experiment which had two factors and four-level:water and nitrogen.And D-saturation optimal regression design.Among them,has 4 levels of moisture are designed according to the optimal code,in order of low water,medium water,multiple water and high water?respectively1800?3363?4310?5400m³/hm²?;there are 4 levels of density,followed by low density,medium density,multiple density and high density?respectively318?470?600?816million/hm²?,moisture and density combination test total 6 treatments.To study the effect of different irrigation volume and density on plant growth,water use efficiency,and density efficiency at each growth stage,through the evaluation of yield and compositional factors,the optimal drip volume and density matching model for winter wheat growth was explored,This will provide reference materials for improving the yield,reasonable irrigation,and reasonable close planting of winter wheat,which will provide basis for future exploration of water-saving and high-yield production.This study shows that:?1?The total number of stems in winter wheat under drip irrigation showed a trend of increasing first and then decreasing.The total number of stems treated with M₂ reached 17.984 million plants/hm²,which was significantly different from other treatments.Increasing the density and irrigation can significantly increase the total number of wheat stems.There was no significant difference between M₄ and M₅ treatments.In the flowering stage,M₆ reached the highest maximum plant height of 77.67cm,and the lowest in M₂ was only56.63cm.Under the same water condition,the plant height decreased gradually with increasing density.At the same density level,plant height increased with irrigation volume.At the booting stage,the maximum leaf area per plant reached a maximum of 227.77cm² for M₆ treatment and then decreased to about33.60-85.43 cm² for the wax ripening period.Under the condition of water-tight interaction,M₅ and M₄could still maintain a large leaf area at the late filling stage and the wax ripe stage,reaching 64.87-68.59cm².The population LAI showed a“low-high-low”trend from jointing to maturity.From the jointing stage to the booting stage,the LAI increased with the increase of density and irrigation volume;after the booting stage,LAI decreased rapidly with the increase of density,while increasing the drip volume decreased the LAI.?2?The photosynthetic rate of M₄ treatment was higher by 4.78 gCO²/m²/h.In the flowering period,M₂reached the maximum population respiration rate of 1.87gCO²/m²/h,but after the flowering period,the population respiration rate of M₂ decreased rapidly,even lower than other treatments.Under the M₄condition,the amount of leaf origin was also the largest,reaching 63.09 CO² mol·m^-2.The dry matter of winter wheat in drip irrigation showed an increasing trend with the growth process.Under the same density condition,the high water treatment was greater than the low water treatment.The M₅ at the flowering stage was 21.82%higher than the M_2.During the jointing stage,M₄ was 18.18%higher than M₆,but from the booting stage,M₆ was higher than M₄ by 9.30%.It showed that with the increase of density,the dry matter accumulation of wheat showed a slow growth trend.The SPAD value of the maximum flag leaf was reached during grain formation,reaching a maximum of 54.87 under M₂ and M₅ treatment and a minimum of 48.81for M₁.At the same density,there was no significant difference between jointing treatments.After the jointing period,the SPAD value of the flag leaf gradually decreased with the increase of the density,and the minimum M₁ was only 19.36.In the booting stage,the water content of leaves increased with the increase of density and irrigation volume,and 96.21%of M₅ treatment was the maximum flag leaf water content.?3?Under the same moisture condition,with the increase of density,the number of panicles increased,but the number of grains per spike and 1000-grain weight decreased,and the yield showed the trend of increasing first and then decreasing.At the same density,the yield factors,number of grains per ear,number of harvested panicles,1000-grain weight,number of effective spikelets and panicle length all increased with the increase of irrigation volume.The yield of M₄ treatment?with a density of 6 million grains/hm²,irrigation volume 3363 m³/hm²?was the highest,reaching 9896.78kg/hm²,the number of panicles for harvest reached 7.620 million/hm²,the number of grains per spike was 26.07 grains/ear,and the grain weight reached 49.81 g.At higher densities,drought stress?M₁?or excessive water?M₂?results in a reduction in the number of effective spikelets,a shorter spike length and an increase in the number of invalid spikelets,a decrease in the number of grains per spike and a thousand grain weight,and overall yield is not high.?4?By analyzing the parameters calculated by the field experiment of the D-saturation optimal regression design,the drip volume and density effect model with the output as the objective function was established.It is calculated that the optimal values of drip volume and density for high-yielding winter wheat under the experimental conditions are 3557.979m³/hm² drip,a density of 6.355 million grains/hm²,and an expected maximum yield of 10119.7 kg/hm².And the density and drip amount have extreme values within the range of experimental factors.Above or below the drip volume or density will cause the yield to decline.For single factor comparisons,the yield effect of drip volume is greater than the density effect,and the interaction effect analysis will increase the effect of water and dense synergy production by simply increasing the irrigation volume or increasing the density.It shows that the drought-irrigated area in southern Xinjiang is mainly based on water and appropriate density adjustment is the key to obtaining high yield.?5?Frequency analysis of multi-function collections of water and dense combination schemes fitted by mathematical models,screening of 10 sets of water with a unit production of 6750 kg/hm2 or more,and 10sets of dense combination schemes,and applying water and density of growth and yield traits.The model was used to calculate the best growth and yield trait reference values for each program,providing reference for the diagnosis and regulation of high-yield wheat.