YAN Wei1, ZENG Cheng2, XIAO Shizhen1,LAN Jiacheng1, DAI Linyu1, TAI Zhiqin1, HE Jianghu1, HE Chun2, DI Yongning1
(1.School of Karst Science ,Guizhou Normal University/State Engineering Technology Institute For Karst Desertification Control, Guiyang 550001, China;
2. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China)
Abstract: There have been many research reports on the influence of land use on limestone dissolution rate, but the research on the response of dolomite dissolution rate to land use is rarely reported. Therefore, exploring the influence of different land uses on the dissolution rate of dolomite is of great significance and can provide a basis for evaluating the effect of karst carbon sinks in the dolomite area. In this paper, a typical small dolomite watershed in the humid subtropical zone—the dolomite watershed of the Huangzhou River in Shibing county, Guizhou province, is used as the research area. The dissolution rate of different land uses in the watershed and its influencing factors are studied using the dolomite dissolution test piece method. The results show that the corrosion rate of the test piece under different land use conditions is in the order of dry land (4.25 mg/(cm2·a))> forest land (1.01 mg/(cm2·a))> paddy field (0.14 mg/(cm2·a)); The dissolution rate of the test piece increases with the increase of soil organic matter and the decrease of soil pH; but it has the opposite trend to the soil CO2 concentration; the soil water content and bulk density have little effect on the dissolution rate. According to the dissolution rate of dolomite samples, the total amount of karst carbon sink in the dolomite basin is estimated to be 351.70 t CO2/a, with a karst carbon sink intensity of 7.31 tCO2/(km2·a), which is significantly smaller than the previous calculation using the hydrochemical runoff method. The difference of these two methods obtained in this study is similar to that observed in limestone areas.
Key word: dolomite basin; dissolution tablet; dissolution rate; carbon sink; land use; Shibing
EARTH AND ENVIRONMENT Vol.49, No.5, Tot No.343, 2021, Page 529-538
