【摘要】 采用碱溶液吸收法通过对重庆金佛山林地、裸地表层岩溶生态系统土壤CO2释放量进行野外监测,研究了影响土壤CO2释放量变化的主要因素,揭示土壤CO2释放变化规律。土壤CO2释放量的变化主要随着温度而变化,即气温降低,土壤CO2释放量减少,在昼夜时段,土壤CO2也随温度而变化,但相比温度变化有明显滞后性;降雨对土壤CO2释放有比较复杂的影响,但非简单的线性相关;同时植被也会影响到土壤CO2的释放,总体上,相比裸地而言,林地的土壤CO2的释放量大,但在不同时间段内土壤CO2释放强度与气温的关系有较大差异。一天时间段内林地土壤CO2释放强度与温度的关系较裸地灵敏,这是因为林地本身生物量大,对温度反应敏感,温度很小的变化就能引发土壤CO2释放量的大幅度地改变。而在以月为单位观测时间段时,裸地土壤CO2释放强度与气温的关系较林地灵敏,这可能是因为植被覆盖减缓气温对土温的影响,对土温有较强的调节作用。这种不同植被系统下,在不同时段土壤的CO2释放量动态差异在讨论岩溶作用与碳循环时应充分注意。更多还原

【Abstract】 Recent studies of the karst process and terrestrial carbon cycling were focused on dnamics of carbon fluxes. The investigation aimed at depicting change of CO₂ release from soil in an epikarst ecosystem of different vegetations in the Jinfu Mountain of Chongqing. The results show that the release amount of CO₂ from soils changes obviously. The change of the release amount of CO₂ is somewhat consistent with the change of temperature, but the change of the former is about several hours later than that of the latter. The temperature is the main factor governing the change of the release amount of CO₂ from soils, and its rising and falling bring about the increase and decrease of the release amount of CO₂. Rain also affects the release of CO₂ from soils. Furthermore, the change of the release amount of CO₂ from soils is also related to the vegetation. The woodland is greater than the uncovered land in affecting the release amount. The release of CO₂ from soil in woodland is more sensitive to temperature than that in the uncovered land during the day time, but the release of CO₂ from soil in the uncovered land is more sensitive to temperature than that in woodland during different months of a year. More importance should be attached to the difference of CO₂ release from soils in different time intervals under different vegetations in the future study of carbon cycle in the karst system.更多还原