Agro-Ecological Suitability Variation Of Chinese Medicinal Yam Under Future Climate Change

Chinese medicinal yam(CMY)is a kind of tonic medicinal material widely used in China.The medicinal properties and active ingredients of yam are closely related to its origin.The yam grown in genuine producing area is the best.The CO2 chemical concentration,light,air temperature,water conditions and soil in genuine producing area are all important factors that affect the yield and quality of Chinese herbal medicines.Under the background of global warming,the CO2 chemical concentration in the atmosphere is likely to increase further.CO2 participates in plant photosynthesis and has an important influence on the plant growth process.Temperature directly affects the activity and respiration rate of enzymes in the photosynthetic carbon cycle.Heating within a certain range can increase kinetic energy,accelerate enzymatic chemical reactions,and also affect the degree of plant stomata opening.Studying the effect of increasing CO2 chemical concentration on photosynthesis chemical reactions and crop yields under the background of climate warming plays a basic guiding role in the field of yam production.This paper studies the changes of temperature and precipitation in China under the background of increasing CO2 chemical concentration,and its impact on the production areas and production potential of Chinese medicinal yam.The main contents are as follows:(1)Using the root-mean-square error,correlation and other statistical indicators to evaluate the spatial-temporal simulation capabilities of regional climate models(RCMs),the results show that the high-resolution regional climate model PRECIS can improve the global climate model HadGEM2-ES when reproducing historical climate by reducing root mean square error of temperature and increasing correlation coefficient.PRECIS improves HadGEM2-ES simulation of precipitation in individual sub-regions such as Southeast and North China.Comparatively speaking,the improvement in temperature is more pronounced than precipitation.(2)Forecasting future climate changes,and analyzing the possible changes of precipitation and temperature considering average climate and extreme climate.The whole country generally receives more precipitation and higher temperature,more high temperature days and increasing precipitation intensity.For the North China yam production area,by the middle of 21st,under the RCP8.5 scenario(by 2100,atmospheric CO2 will increase to 936 ppm,CH4 to 3751 ppb,and N2O to 435 ppb),the water decreases by about 10%and the temperature increases by about 2?.(3)Based on the AEZ model with CMY parameter,driven by high resolution regional climate model PRECIS,the paper assesses the suitable planting areas of CMY under the influence of global warming and CO2 increasing.The simulation finds that in the 2050s,Henan might reduce production slightly due to wetter environment.In addition,the improvement of the thermal conditions in the north and the increase of the chemical concentration of CO2 cause the adaptation area of yam to expand northward to around 123N.The results show that as the temperature higher and the CO2 chemical concentration increasing,yam photosynthesis will further flourish,the product of non-structural carbohydrates accumulate more,suitable areas of yam will expand to the north,and the output will increase.In the future,the drought period may be prolonged in the yam-producing regions of North China,especially near Shandong,and further preparation for drought prevention is needed.