Effects Of Regulated Deficit Irrigation On Corn Growth And Water Utilization

Heilongjiang Province is my country’s main food production base.Corn is one of the five major food crops in Heilongjiang.Its planting area has gradually increased from 2002 to 2016.By 2021,it has already surpassed rice to become the largest food crop in Heilongjiang Province.The western part of Heilongjiang Province is a dry farming area with insufficient water resources.Seasonal drought is the main factor restricting grain production in this area.Based on this,in order to realize the sustainable use of regional agricultural water resources,it is necessary to carry out research on efficient and water-saving planting patterns for the main food crops in the region.This paper uses the method of measuring tube test to explore the effects of different water treatments on corn growth dynamics,water consumption,yield and its components,and water use efficiency,and further clarifies the correlation between corn traits and yield,and uses entropy weight-The TOPSIS method comprehensively evaluates the test.There are 14 kinds of treatments in this paper.Except for full irrigation treatment(soil moisture content during the whole growth period 80%-90%)and suitable irrigation treatment(soil moisture content during the whole growth period 70%-80%,control group),there are different Growth stages(seedling stage,jointing stage,tasseling stage,filling stage),different water deficit levels(severe water deficit 50%-60%,moderate water deficit 55%-65%,mild water deficit 60%-70&)are Divide and set 12 water deficit treatments,namely,severe at seedling stage,moderate at seedling stage,mild at seedling stage,severe at jointing stage,moderate at jointing stage,mild at jointing stage,severe at tasseling stage,moderate at tasseling stage,mild at tasseling stage,and filling stage Severe,medium grouting period,and mild water deficit treatment in grouting period.The results of the study are as follows:(1)Water deficit at seedling stage does not change the original growth trend of corn plant height,stem thickness and leaf area.The plant height and stem thickness of water-deficient maize at the seedling stage showed a rapid growth and then remained basically unchanged.The plant height of the moderate water-deficit treatment at the seedling stage was 7%higher than the control level,and only showed growth inhibition at the seedling stage.After the jointing stage rehydration,there is a significant growth compensation effect,and this compensation effect continues to the tasseling stage.However,the plant heights of severe and light water deficit treatments in the seedling stage were lower than the control by 9.1%and 6.4%,and continued to be lower than the control level during the whole growth period.Each water deficit treatment at the seedling stage had little effect on the stem thickness,and the stem thickness of each water deficit treatment fluctuated up and down at the control level.The leaf area grows in an inverted U shape.The leaf area increases rapidly before the jointing stage,changes steadily before the filling stage,and gradually decreases after the filling stage.The leaf area of each water deficit treatment at the seedling stage is 635.2cm~2,624.9cm~2,respectively.648.0cm~2,all higher than the control level,water deficit at the seedling stage promotes the formation of leaf area,is conducive to the progress of photosynthesis,and has the effect of maintaining yield.The stem thickness of the water deficit treatment at the jointing stage showed a trend of rapid increase before the jointing stage and then remained unchanged.Compared with the water deficit at the seedling stage,the growth of the stem thickness mainly occurred in the seedling stage.Water deficit at the jointing stage inhibits the growth of plant height to a certain extent,and the greater the water deficit,the stronger the inhibitory effect.After the tasseling stage re-watering,the plant height of the corn appears to be compensated for growth.All water deficit treatments during the tasseling period have basically no effect on the corn stem thickness and leaf area,but exhibited an inhibitory effect on the growth of the plant height.The plant height of the severely water deficit treatment during the tasseling period basically stopped growing after the water deficit.There is no sign of continued growth,indicating that the tasseling period is a critical period for corn plant height growth.The water deficit treatment during the filling stage has basically no effect on the vegetative growth of the plants.The filling stage is the later stage of plant growth,and the vegetative growth of the plant mainly occurs in the early stage of growth,and the reproductive growth of the plant is mainly carried out in the later stage of growth.The root-to-shoot ratios of severe water deficit at seedling stage and severe water deficit at jointing stage were 0.44 and 0.41,respectively,which increased by 77.0%and 64.0%compared with the control,which can significantly improve the lodging resistance of plants.When plants are subjected to water stress,the root system cannot absorb enough The water content meets the plant’s growth needs,and the dry matter distribution tilts toward the root system.The greater the water deficit in the jointing stage,the more obvious the increase in root-to-shoot ratio.In the late growth period,reproductive growth is mainly carried out,and the water required is relatively small,and the sensitivity to water is low,so the root-to-shoot ratio does not change significantly.(2)The ear length and ear thickness of different water deficit treatments in each growth period were slightly higher than the control level.Except for the moderate water deficit treatment in the seedling stage,the bald tip length of corn was significantly higher than the control level in the other water deficit treatments.The organ growth of corn mainly occurred in the late growth period.To a certain extent,inhibit the growth of corn kernels.There is no significant difference between the 100-seed weight of different water treatments and the control.The water consumption and yield of corn plants after water deficit treatment were lower than the control level except for moderate water deficit treatment in the seedling stage,and the yield reduction rate increased with the increase of water deficit.The water use efficiency of the moderate water deficit treatment in the seedling stage was 11.1%higher than that of the control,which can achieve the effect of saving water and maintaining production.(3)Through the correlation analysis of corn traits and yield,it can be seen that the coefficient of variation of the above-ground dry matter quality,bald tip length,root to shoot ratio,and root dry weight is between 27%and 44.4%,which is easily affected by water.The coefficient of variation of plant height,stem thickness,leaf area,ear length,ear thickness,100-grain weight,is between 3.5%and 8.1%,which is not easily affected by water.The correlation coefficient between yield and plant height was 0.810,showing a very significant positive correlation(P<0.01),and the correlation coefficient with hundred-grain weight was 0.610,showing a significant positive correlation(P<0.05),and the correlation coefficient with bald tip length was-0.780,showing a very significant negative correlation,with a correlation coefficient of-0.651 with the root-shoot ratio,showing a significant negative correlation.It shows that under different water treatment conditions,the height of the plant,the weight of a hundred seeds,the length of the bald tip,and the small root-to-shoot ratio are beneficial to the high yield of maize.Except for the root-shoot ratio,the correlations between other traits and yield are all affected by traits other than itself.(4)Using the entropy weight-TOPSIS method,select 7 indicators from corn growth indicators and water-saving and yield-increasing indicators,namely plant height,bald tip length,root to shoot ratio,100-kernel weight,irrigation volume,yield,and water use efficiency.Comprehensive evaluation of the regulated deficit irrigation mode of corn in western Heilongjiang.The order of the schemes is:moderate water deficit treatment at seedling stage>mild water deficit treatment at filling stage>control treatment>mild water deficit treatment at jointing stage>adequate irrigation>moderate deficit at jointing stage Water treatment>mild water deficit treatment at tasseling stage>mild water deficit treatment at seedling stage)>severe water deficit treatment at seedling stage>severe water deficit treatment at jointing stage>moderate water deficit treatment at tasseling stage>moderate water deficit treatment at grouting stage>grouting stage Severe water deficit treatment>Severe water deficit treatment in tasseling stage,moderate water deficit treatment in seedling stage and mild water deficit treatment in filling stage get close degree C values of0.67757 and 0.60506,respectively,which are higher than the C value of control treatment of 0.58351,indicating that the seedlings Both the medium water deficit and the light water deficit during the grouting period can produce stronger water-saving and stable production capacity than suitable for irrigation.Finally,it is concluded that the moderate water deficit in the seedling stage is the best irrigation mode in the western region of Heilongjiang Province.