喀斯特地区浅层地下水对植被退化的水文地球化学响应——以贵州荔波拉桥小流域为例

喀斯特地区植被退化的水文地球化学响应是喀斯特研究的重要内容之一,具有重要的科学和现实意义。选择贵州荔波拉桥小流域中四个不同植被类型的样地作为对象,按月采集浅层地下水(土壤水和表层泉水),对其进行水文地球化学各参数的分析。结果表明,土壤水中Ca2+、Mg2+、HCO3-、EC和pH值,表层泉水中Cl-、NO3-和SO24-等对植被退化响应敏感;而土壤水中NO3-和SO24-,表层泉水中Mg2+、NH4+、HCO3-和EC,以及土壤水和表层泉水中δ13 CDIC值则可能还受到其他过程的影响,需谨慎使用。由此可见,对于土壤层,阳离子和与土壤CO2气体浓度有关的HCO3-可能有较好的响应,而对于表层泉水,HCO3-以外的阴离子可能更敏感。

Hydro-geochemical Response of Shallow Groundwater on Vegetation Degradation in Karst Area:A Case Study in Laqiao Catchment of Libo in Guizhou,China

It is very important that geochemical response of vegetation degradation is studied in karst area,which has an important scientific and practical significance.Four sample plots with different types of vegetation were selected as a study object in Laqiao catchment of Libo in Guizhou,China.Shallow groundwaters(soil water and epikarst spring) were sampled monthly at the four plots,respectively,and their main hydrogeochemical parameters were measured.Results show that Ca2+,Mg2+,HCO-3,EC and pH value in the soil waters,and Cl-,NO-3 and SO2-4 in the epikarst springs are sensitive to vegetation degradation.However,we should be cautious when using those parameters that maybe are affected by more complex processes,such as NO-3 and SO2-4 in the soil waters,Mg2+,NH+4,HCO-3 and EC etc.in the epikarst springs,and δ13CDIC value in the soil waters and epikarst springs.Thus,the cations and HCO-3 that is affected mainly by soil CO2 gas concentration in the soil layer may have a good potential to respond vegetation variation,and the anions except for HCO-3 maybe are more sensitive in the epikarst springs.