Effects Of Waterlogging Stress On Carbon Flux And Growth Of Winter Wheat In Huaibei Plain

Waterlogging stress is one of the important environmental factors affecting the carbon flux and winter wheat growth.The study of waterlogging stress effects on carbon flux and winter wheat growth provides a theoretical basis for exploring the carbon balance and growth condition of farmland ecosystem under waterlogging stress.In this study,a typical experimental area was set up at the Wudaogou Experimental Station in Bengbu,Anhui Province.The controlled experiment sustained and included9 growth stages of winter wheat,namely,9 groups of different growth stages under surface waterlogging stress,3 groups under subsurface waterlogging stress,and 3groups of all growth stages set for contrast.Based on these data to calculate followings:the carbon flux of winter wheat in three experimental plots in each growth stage;the leaf area of tested winter wheat in the test group in joint stage;the plant height and yield structure of winter wheat in different growth under waterlogging stress after harvest;the theoretical yield of winter.The trend of winter wheat carbon flux as well as the effects of waterlogging stress on winter wheat growth under three scenarios were analyzed.The main contents and results of this research are summarized as follows:?1?The features of winter wheat carbon flux under different scenariosIn the controlled group,the carbon flux of winter wheat at seed stage and ripe stage was in the form of carbon source,At 9 o'clock,the maximum average carbon flux was0.46(mg/m²·s^-1)in ripe stage.In other growth stages,the form was carbon sink,and the carbon flux decreased gradually with the growth stages,at 9 o'clock,the lowest average daily carbon flux was-6.00(mg/m²·s^-1)in fill stage.Under the waterlogging stress,the carbon flux of winter wheat had a decreasing trend.In the seed,green and boot stages,the subsurface waterlogging had better effects of reducing the carbon flux than the surface waterlogging,which mainly affected the carbon flux at 13 o'clock,the maximum reduction ratio of subsurface waterlogging was-1.08(mg/m²·s^-1)in seed stage,-3.06(mg/m²·s^-1)in green atage,-3.28(mg/m²·s^-1)in boot stage;in the tiller stages,the subsurface waterlogging had the same effects of reducing the carbon flux as the surface waterlogging,which mainly affected the carbon flux at 9 o'clock and 13 o'clock,maximum reduction ratio of subsurface waterlogging was-2.01(mg/m²·s^-1);in the joint stage,the surface waterlogging had better effects of reducing the carbon flux than the subsurface waterlogging,and the surface waterlogging mainly affected 9 o'clock whereas the subsurface waterlogging mainly affected 13 o'clock,maximum reduction ratio of surface waterlogging was-3.77(mg/m²·s^-1);in the head,flower,fill and ripe stages,the waterlogging stress no longer reduced the carbon flux.?2?The relationship between carbon flux and weather as well as temperatureOn sunny days,the carbon flux tended to remain flat after a slow decline,whereas on rainy days,it tended to remain flat after rising day by day.The carbon flux decreased significantly on the sunny day after continuous rainy days.The carbon flux had a regular trend of rising,then falling and then rising with temperature.Under the subsurface waterlogging and in the controlled group,in previous year,the optimum temperature for the carbon flux to recline was reduced followed the growth stages and was risen in the next year,The lowest temperature is-1?at tiller stage and the highest is 22?at fill stage..There were fewer data under surface waterlogging and there were errors at the inflection point,but the trend was similar to the other two scenarios.?3?The waterlogging effects on yieldCompared with subsurface waterlogging stress,surface waterlogging stress was more likely to lead to yield loss of winter wheat,which had significant decline in seed,joint,boot,head and flower stages,the maximum yield reduction was-38.4%at flower stage.Among them,in the seed and joint stages,such effects had greater influence on the kernel number,The decline ratio of surface waterlogging was-23.41%.and in joint,boot stage and head stages,such effects had greater influence on the spike number,in waterlogging scenarios,the decline ratios were-19.41%,-15.79%and-16.45%respectively.In other growth stages like the tiller and green stages,the spike number and thousand kernel weight increased,and the yield loss decreased.In the fill stage,the thousand kernel weight was greatly increased,and the yield loss was also small;in the ripe stage,all elements of winter wheat had little affects.?4?Combined analysis of carbon flux and yield under waterlogging stressIn the tiller and green stage,there were slight subsurface waterlogging,which could reduce carbon flux and had less influence on yield.A slight subsurface waterlogging occurs in the seed and boot stages,which could slightly reduce the carbon flux,and the yield also decreased to a certain degree.In the fill stage,slight subsurface waterlogging led to yield increase within a small range,but the carbon flux would increase accordingly.In other growth stages,the waterlogging stress should be avoided as much as possible.