Response Of Soil Carbon Mineralization And Priming Effect To Simulated Warming Along An Elevation Gradient In Wuyi Mountain,China

Terrestrial ecosystem contains a significant amount of the world’s pool of soil organic carbon.The slightest change in it will affect the concentration of the carbon dioxide in the atmosphere.The relationship between soil organic carbon and global warming is controversial,one reason is that we don’t know whether the increased productive forces will offset the growth of soil organic carbon emissions or not.So it is necessary to discuss the influence of soil organic carbon(SOC)to climate change and predict future climate changes.In this study,soil organic carbon(SOC)pool and the characteristic of carbon mineralization are studied in four classic vegetation communities with the elevation gradient in Wuyi Mountain.Here,we use the method of indoor incubation in two different ways.One is by using the mean atmospheric temperature(EBF 17℃、CF 13℃、SDF and AM 9℃),and the other by increasing the temperature(+4℃,such as:EBF 21℃、CF17℃、SDF and AM13℃)in the process of incubation,by adding different properties like exogenous substrate(glucose,lignin).Finally,this article observes the response of soil carbon mineralization and its priming effect.It discusses how different elevations of soil organic carbon simulates response mechanism regarding global warming along the elevation gradient in Wuyi Mountain,China.Its results are valuable to evaluating the response of soil organic carbon along the elevation gradient of future regional climate change.The main results are as followed:(1)Soil organic carbon and total nitrogen increase as the elevation increases.The average mineralization rate of CF is significantly higher than others and the SDF’s is lower.There is no significant difference between the average mineralization rate and cumulative mineralization of AM and EBF,which is probably because it’s difference is decided by the change in the incubation temperature,organic matter content and dissolved organic carbon,nutrient elements,microbial.(2)The increase in temperature significantly increases soil organic carbon mineralization rate,and the increase of soil organic carbon mineralization rate have a declining trend along an elevation gradient.The increased cumulative mineralization of EBF amount is significantly higher than other elevations.This may be because the higher the temperature in the EBF,the more significant is the increase of mineralized EBF.At the same time,the increase of temperature in EBF after the increase of soil nutrient availability is significantly higher than other elevations,and the more prominent is the change in it’s microbial community structure.The increase of temperature in the mineralization ratio shows a declining trend along the elevation gradient.The results states that once the temperature increases in the future,low altitudes soil organic carbon mineralization rate will increase.(3)Adding Carbon significantly increases soil mineralization rate,and by adding glucose,the mineralization rate is significantly greater than by adding lignin.By adding glucose the priming effect is significantly higher than adding lignin,EBF,SDF is higher than CF,AM.It may be caused by the difference of exogenous substrate,nutrient elements availability and microbial community structure.Compared to complex carbon compounds,simple carbon compounds is easier to use,and it increases the rate of soil respiration.At the same time,the microbial community structure of EBF,SDF GP:GN ratio is significantly higher than CF,AM.The F:B ratio is significantly lower than CF,AM.Different studies show that the increase of litter will promote the decomposition of soil organic carbon,the increase of easily decomposed litter causes more release of CO2 compared to that of litters that are harder to decompose.(4)The increase in temperature reduces the intensity of priming effect of soil organic carbon.This may be because,temperature increase does not get affected by the addition of carbon,while priming effect promotes original organic carbon decomposition by activating microbial activity to release more extracellular enzymes.And the increase of temperature also lowers the activation energy of soil organic carbon,which also accelerates the decomposition of soil organic carbon.Secondly,in an environment with higher temperature,soil extracellular enzyme activity is better in the process of decomposition of soil organic carbon.At this time,the priming effect is limited in the extent of soil organic carbon decomposition rate increase.In conclusion,global warming can,at a certain extent reduce the amount of carbon emitted by increased productivity.