Carbonate Rock Dissolution Rates and Their Influencing Factors under Different Vegetation Types in Karst Areas of Guizhou
To explore the characteristics and influencing factors of carbonate rock dissolution in diverse vegetation types among different karst areas,correlation regression and random forest analysis,dissolution testing as well as other statistical methods were used to quan-tify the dissolution rate and influencing factors of different vegetation types(arbor forest,shrub forest and grassland)in four karst areas in Guizhou:the Maolan National Nature Reserve(ML),Shazi Township in Zhenning County(SZ),Zhengtun Town in Xingyi City(ZT),and Ganzhucao in Shibing County(GZ).The results show that the average dissolution rate of bedrock and standard rock tablets in different karst areas over one year and one and a half years ranged from 2.37 to 7.42 mg/(cm2·a).The dissolution rate was in or-der of SZ＞GZ＞ML＞ZT.The dissolution rates of standard rock tablets were generally higher than that of bedrock tablets,but the oppo-site situation also existed;the dissolution increments from one year to one and a half years were greater in arbor forests than in shrub forests and grasslands.There were remarkable differences in the dissolution rates of carbonate rocks under different vegetation types a-mong the four karst areas.The dissolution rates in ML and GZ were in order of arbor forest＞shrub forest＞grassland,while the dissolu-tion rates in SZ and ZT were higher in shrub forests than that in arbor forests and grasslands,indicating that arbor and shrub forests in different karst areas can significantly promote carbonate rock dissolution.At the soil depth of 0-30 cm,the dissolution rate increased with the soil depth.The dissolution rates in ML and ZT were mainly affected by soil CO2 content and pH,whereas the dissolution rate in SZ was mainly governed by soil pH and water content.In comparison,the dissolution rate in GZ was mainly influenced by soil CO2 and organic carbon contents,reflecting that soil physicochemical properties have different impacts on dissolution rates in different karst areas.Overall,the dissolution rates of the four karst areas were mainly influenced by CO2,total phosphorus and water contents in soils and soil pH.The degree of influence followed the order of:soil CO2 content＞soil pH＞soil total phosphorus＞soil water content.This re-search can provide reference for accurate estimation of karst carbon sinks and ecological restoration and protection.
karst area of Guizhou provincedissolution ratevegetation typeinfluencing factors
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