Effects Of Drought Stress On Growth And Yield Of Winter Wheat And Summer Corn

Due to the global climate change and the intensification of human activities,the water cycle on the earth has undergone dramatic changes,resulting in serious water resources and water environmental crises in many regions and basins.In view of the drought disaster in Huang Huai area,the drought,drought and heavy drought stress were used in different growth periods to study the response of winter wheat and summer maize plant height,leaf area,photosynthetic characteristics,yield and water use efficiency to drought stress.It will provide certain technical basis for optimizing the irrigation system and predicting the impact of drought stress on the development trend of wheat and corn in the future,and achieves the following main results:1)Plant height and leaf area are the direct effects of water stress on winter wheat and summer corn morphology.Winter wheat and summer corn reduce water use by reducing transpiration and water stress by reducing plant height and leaf area.Whether it is winter wheat or summer corn,the jointing stage is the key water-reproductive period of plant height and leaf area of the two crops.Under moderate and severe water stress,the plant height of winter wheat decreased by18.6% and 29% compared with CK,and leaf area decreased by 18.2% and 49.5%compared with CK.Under moderate and severe water stress,the plant height of maize was reduced by 11.4% and 28.5%,respectively,compared with that of CK.Leaf area was reduced by 10.1% and 23.2%,respectively,compared with CK.During this period,water stress can significantly affect the plant height and leaf area of winter wheat and summer corn.2)Different levels of water stress at different growth stages have different effects on the photosynthetic characteristics of winter wheat and summer corn.Water stress inhibited the photosynthesis of the leaves,and the degree of inhibition of photosynthetic and stomatal conductance was positively correlated with the degree of stress.After being rehydrated under water stress,the photosynthetic performance of winter wheat had different compensatory effects during different stress periods.Among them,the net photosynthetic rate and stomatal conductance of winter wheat at the filling stage were the lowest.Stomatal conductance decreased by 28.7%,34%,and49.4% compared with CK,and net photosynthetic rate decreased by 10.5%,23.2%,and 28.0% compared with CK.Photosynthesis of maize leaves was more sensitive to water stress during the flowering-filling period.After 10 days of re-watering,thestomatal conductance of T6 treated maize was reduced by 44.5% compared with CK,and the net photosynthetic rate was reduced by 26.7% compared with CK.3)The effect of water stress treatment on the yield of winter wheat increased with the increase of the degree of stress,and any degree of water stress would reduce the number of effective panicles,grains per ear,and the yield per plant,and the moderate and severe water stress treatment of wheat yield.The decline is more significant.Water stress at jointing stage and heading stage resulted in a decrease in the number of glutinous spikelets in wheat and reduced the number of effective panicles and grains per panicle,which resulted in a decline in yield.Water quality during grain filling caused the grain quality of 1000 grains to decrease,and grain dried up,causing a decrease in yield.Flowering-filling stage is the key water requirement period for the formation of summer maize yield,and the water stress at this time will have a significant impact on the grain filling process,leading to a serious reduction in corn yield.4)Water stress has an adverse effect on the growth of corn root caps.The greater the degree of stress,the greater the root to crown ratio.From different stages of growth,water stress can increase the ratio of root to shoot of corn,but different stages of water change have different effects on the distribution ratio of dry matter between roots and crowns,and water stress increases during flowering and grain filling stages.The effect of the root-to-crown ratio is higher than the water stress from the jointing stage to the tasselling stage,and regardless of the degree of water stress during the milk ripening stage,the root dry weight accounts for 3%-5% of the total dry weight,and the root-shoot ratio tends to be uniform.The dry matter accumulation in different organs of different maize plants treated with different water stress showed the same change trend of the same organs.The dry weight of stem and leaf of each plant increased gradually in the proportion of dry matter accumulation.The proportion of accumulation has gradually decreased.5)Excessive or too little irrigation water significantly affected the utilization efficiency of soil moisture in winter wheat.Re-watering after light water stress at jointing stage had no difference between the single barrel yield and the CK treatment of winter wheat,and the water use efficiency was higher than that of CK treatment,and other water stress treatments.After rewatering,some compensatory effects also appeared,but the compensation effect was poor.Single barrel production and water use efficiency were lower than CK treatment.Water stress in the jointing-heading stage and flowering-filling stage showed that the yield of the maize decreased with the increase of the water stress degree.There was no significant difference between the yield of water and the CK and the water use efficiency was higher than that of the CK.The water use efficiency of BL and CK treatments increased by 8.7% and 2.8%,respectively,compared with CK.