桂林盘龙洞岩溶表层带土壤CO2浓度的季节变化研究

以桂林盘龙洞岩溶实验场为例,选择岩溶洼地里的坡地和洼地2个样地,通过长期定时监测土壤CO2浓度变化,表明:(1)土壤CO2浓度具有明显的季节性变化特征,夏季(6-8月)土壤CO2浓度是其它时期的2～3倍,并显示与气温、降水和生物活动密切相关;(2)洼地地段土壤CO2浓度比坡地地段要高,尤其夏季时洼地比坡地高近1000mg/m2;(3)在垂直剖面上,大多数的情况下土壤CO2浓度随土壤深度的递增而升高,但在雨季时坡地(-50cm与-80cm处)和洼地(-80cm与-100cm处)的土壤CO2浓度随深度的增加而降低。 

The seasonal variation of soil CO2 concentration in epikarst in the Panlong Cave, Guilin

Taking the Panlong Cave karst experimental site in Guilin as a case, long-term survey on soil CO₂ concentration variations at regular intervals is done in two sample plots depression bottom and slope. The result shows that:(1) The soil CO₂ concentration varies seasonally obviously. In the summer (May to August), the soil CO₂ concentration is two or three times higher than that in the other periods. And it is closely related with temperature, precipitation and biological activities; (2)The soil CO₂ concentration at the depression bottom is higher than that on the slope, especially in the summer, the soil CO₂ concentration at the depression bottom nearly 1000 mg/m2 higher than on the slope; (3)In the vertical profile, the soil CO₂ concentration increases with depth in most cases, but the CO₂ concentration both on the slope(-50 cm and -80 cm)or at the depression bottom(-80 cm and -100 cm)reduce with soil depth during the rainy season, which make the soil CO₂ concentration to increase with the depth at the top and decrease at the bottom of the vertical profile.