Effects Of Fire Activity On Carbon Content Of Phytolith

The reconstruction of ancient fires is conducive to understanding the law and mechanism of fire occurrence,and provides a foundation for fire prevention management and ecological restoration.The burned phytolith index is an important indicator,but the source of carbon black of burned phytolith is still controversial,the burial process can change the color and transparency of phytolith,the identification of burned phytolith still lacks evidence of carbon content change,and whether the carbon content of phytolith has fire indication significance is not clear.In this study,ashed phytolith was extracted by modern plant combustion experiment,and the changes of phytolith carbon content and dissolution rate were analyzed.The surface soil of forest fire area,transition area and non-fire area was collected,soil phytolith was extracted,and its carbon content and dissolution rate were analyzed.Accordingly,the influence of fire activity on the carbon content of phytolith was determined,and its potential indicative significance on fire activity was determined,and the effect of fire activity on carbon sequestration by phytolith was evaluated.The main insights are as follows:(1)Ashed phytolith extracted by burned plants and carried out bleaching experimental treatment,and the carbon content was analyzed,and the carbon content was as follows: ashed phytolith>ashed phytolith with bleaching>modern plant phytolith,and the increase in carbon content of ashed phytolith mainly came from carbon black adsorption;In the surface soil of forest fire area,transition area and non-fire area,the carbon content of phytolith in descending order is: phytolith in fire area> phytolith in transition area and phytolith in non-fire area.The carbon content of phytolith is able to distinguish different areas of fire.(2)The morphological distribution law of ash burning phytolith is as follows: the large form of burning plant phytolith,such as ELONGATE and BULLFORM FLABELLATE,is easy to turn black,while short cells(BILOBATE,SADDLE,RONDEL)and hair cells are not easy to change color,and the proportion of different forms of phytolith turning black is not the same,which is affected by the type of vegetation and the degree of combustion and fire intensity;The ratio of the number of microcarbon to phytolith showed that the fire area> transition area > non-fire area,and the Ch/Ph value was mainly affected by the concentration of microcarbon,which could distinguish the burned and unburned areas.(3)In the combustion experiment,it was found that the dissolution rate of phytolith from slow to fast was: ashed phytolith < modern plant phytolith;In forest fire areas,transition areas and non-fire areas,the soil dissolution rate is: phytolith in fire area<phytolith in transition area< phytolith in non-fire area.Plant ashed phytolith may adsorb carbon black,carbon black antioxidant,and increase the dissolution stability of phytolith.The results show that the carbon content of phytolith,the formation of burned phytolith and the speed of silica dissolution rate are closely related to fire activity,and the carbon content of phytolith can be used as a potential indicator for fire activity reconstruction,which is conducive to soil phytolith carbon sequestration.