关键词: CO₂, 林龄, 氮沉降, 林火, InTEC模型, 净初级生产力, 气候变化

Abstract: Drying wetting (DW) cycles have important influence on soil carbon mineralization, nutrient cycle, and microbial growth and metabolism. Soil samples (0-10 cm layer) were taken from three different elevations in Wuyi Mountain, and were incubated under temperature of 5, 15 and 25 ℃ in the laboratory, respectively. DW and constant water content (CW) treatments were set to examine the effects of dryingwetting on soil carbon mineralization. The results showed that, compared to CW treatment, carbon mineralization significantly decreased when the soil became dry. When the dry soils were rewetted, a flush of mineralized C was observed. Such pulse effect of rewetting gradually decreased with the increases of DW cycles. The cumulative soil carbonmineralization of DW treatment was significantly lower than that of CW treatment, indicating that the amount of pulse mineralized C in rewetting of dry soil was not enough to compensate for the reduction of mineralized C during the drought period. The temperature sensitivity (Q₁₀) in the DW treatment was significantly lower than that in the CW treatment. In DW treatment, the moisture sensitivity (k) increased with the elevation, indicating that soil mineralization was more dependent on moisture in high elevation than in low elevation. Microbial biomass carbon content of DW treatment was higher than that of CW treatment, while dissolved organic carbon content of cold and hot water extraction was lower than that of CW treatment.

Key words: CO₂, forest age, nitrogen deposition, forest fire, InTEC model, net primary productivity, climate change