Soil respiration of Pinus koraiensis and P. sylvestriformis trees growing at levated CO2 concentration
CO2浓度升高对红松和长白松土壤呼吸作用的影响

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.