CO2浓度升高对红松和长白松土壤呼吸作用的影响

以开顶箱法研究了CO₂浓度升高对红松和长白松土壤呼吸作用的影响.结果表明，500 μmol CO₂·mol^-1使红松和长白松土壤呼吸速率明显降低，土壤表面CO₂浓度升高导致CO₂扩散受阻可能是土壤呼吸受到抑制的主要原因.500 μmol CO₂·mol^-1下两树种土壤表面CO₂浓度明显高于对照箱和裸地条件下的CO₂浓度，增加幅度在40～150 μmol·mol^-1之间；对照箱内长白松土壤表面CO₂浓度略高于裸地，差异不显著，红松差异显著500 μmol CO₂·mol^-1下的长白松土壤全氮及总有机碳含量略高于对照组，差异不显著，红松裸地的碳氮含量明显低于500 μmol CO₂·mol^-1 及对照箱内土壤碳氮含量；500 μmol CO₂·mol^-1 及开顶箱的微环境对地下3 cm处土壤温度没有明显影响.

Soil respiration of Pinus koraiensis and P. sylvestriformis trees growing at levated CO2 concentration

The study with open-top chamber showed that at 500 micromol CO2 x mol(-1), the soil respiration rate under Pinus koraiensis and P. sylvestriformis decreased significantly, probably due to the slow diffusion of increased soil surface CO2 concentration. The soil surface CO2 concentration at 500 micromol CO2 x mol(-1) was significant higher than that in the control chamber and un-chambered field, with an increment of 40-150 micromol CO2 x mol(-1). The soil surface CO2 concentration of P. sylvestriformis in the control chamber was higher than that on unchambered field, but the difference was not significant, while a significant difference was observed in P. koraiensis. The total nitrogen and total organic carbon contents in P. sylvestriformis soil at 500 micromol CO2 x mol(-1) had no significant difference with those in the control chamber and on unchambered field, while their contents in P. koraiensis soil were significantly lower on unchambered field than those in the control chamber and at 500 micromol CO2 x mol(-1). Elevated CO2 and the microenvironment of open-top chamber had little effect on the soil temperature at 3 cm depth.