岩溶土壤系统对空气CO_(2)的吸收及其对陆地系统碳汇的意义——以桂林丫吉村岩溶试验场的野外观测和模拟实验为例

SINK EFFECT OF KARST SOIL SYSTEM ON ATMOSPHERIC CO_(2):EVIDENCE FROM FIELD OBSERVATION AND SIMULATION EXPERIMENT

以桂林丫吉村岩溶实验场为例 ,对湿润亚热带岩溶土壤系统进行了土壤植被系统CO2 浓度变化、土壤有机质分解的CO2 产生等野外观测以及实验室土壤灰岩土柱系统模拟实验。实验表明在土壤地球化学条件的控制下 ,岩溶土壤系统存在着对空气CO2 的显著吸收效应 ,其值可达 2 2～ 130 g/ (m2 ·a) ,并以此为依据估算了中国岩溶土壤系统对大气的碳汇约为 4× 10 13g/a。因而揭示了岩溶土壤系统可能是十分重要的陆地碳汇 ,在讨论全球碳汇饱和问题中必须重视这一碳汇的变化。

The authors have made field observations of depth distribution of soil air CO 2 concentration and the dynamics with seasons in Yaji Karst Experiment Site, Guilin for years. Simulated soil rock system experiment was conducted to investigate the CO 2 sink in by soil. The field mono peak of depth distribution of soil air CO 2 concentration demonstrated that soil air CO 2 was consumed in deep soil. The air CO 2 absorption intensity of the bared rock is 9.70 g/(m 2·a), whereas that of the soil ranges from 22g/(m 2·a) to 131 g/(m 2·a). Based on these data, the total sink for air CO 2 by the karst soil system in China is estimated to be 4×10 13 g/a. It is suggested that attention should be given to the role of karst soil system in consuming atmospheric and its dynamic evolution when the problem of global terrestrial CO 2 sink is addressed.