不同植被下土壤碳转移对岩溶动力系统中碳循环的影响

INFLUENCE OF SOIL CARBON TRANSFER UNDER DIFFERENT VEGETATIONS ON CARBON CYCLE OF KARST DYNAMICS SYSTEM

土壤是陆地生物生长、发育、繁殖的最佳场所,也是岩溶发育最为活跃的部位。土壤～岩石(土箱)、草本植物(麦冬)-土壤-岩石(草箱)、木本植物(黄杨)-土壤-岩石(树箱)体系中碳循环的模拟试验显示,黄杨具有较大的树冠可截获更多的降雨,根系的呼吸作用、分泌作用和土壤微生物活力的提高,使土壤环境中CO2浓度提高,树箱比土箱、草箱分别提高148.08%、75.01%,而土壤呼吸排放CO2的量则分别提高175.75%、171.14%;随水排泄的无机碳浓度分别提高77.78%、72.49%,排泄的总量分别提高166.49%、153.81%。碳循环强度的增加,使土下碳酸盐岩的侵蚀能力加强,树箱比土箱提高2.84倍、比草箱提高1.36倍。

Soil is the most important medium for terrestrial organisms to grow, develop and reproduce, and also is an active medium of karstification. Simulation experiment involving soil-limestone (SL), herb (Liriope spicata)-soil-limestone (HSL) and arbor (Buxus sinia)-soil-limestone (ASL) was carried out. The results showed that the ASL system can get more rainwater due to its large crown,and the rich root-system of Buxus sinia results in stronger root respiration and soil microorganic activity. Therefore, compared with that of the SL and HSL, the soil CO_2 concentrations of ASL increase by 148.08% and 75.01% and the CO_2 flux through soil respiration of ASL increases by 175.75% and 171.14%. Meanwhile, the HCO_3^- concentrations in discharged water of ASL increase by 77.78% and 72.49%, the HCO_3^- flux increases by 166.49% and 153.81%. With increasing soil carbon cycling, the dissolution of carbonate rocks under soil will be speeded up. The rate of carbonate rock dissolution under soil of ASL is 2.84 times and 1.36 times higher than that of AS and HSL.