Abstract: With the expansion of urban area and the conversion of non-urbanized landscape to urbanized one, more attention was paid on the urban ecosystem carbo n cycle. Taking the natural and manually managed urban green lands in Fuzhou Cit y as test objectives, this paper studied the profile distributions of soil disso lved organic carbon, microbial biomass carbon, and catalase and urease activitie s. Comparing with natural green lands, the manually managed urban green lands ha d obviously higher soil dissolved organic carbon content but lower soil microbia l biomass carbon content and lower urease activity. The soil dissolved organic c arbon, microbial biomass carbon, and enzyme activities of the two kinds of green lands all decreased with increasing soil depth. A significant positive correlat ion was observed between soil catalase activity and dissolved organic carbon in 0〖KG-*2〗-〖KG-*7〗10 cm layer, and between soil urease activity and microbial biomass carbon in 10〖KG-*2〗-〖KG-*7〗20 cm layer.

Key words: Phosphorus, Sulphur, Bio-cycling, Alpine Tundra, Changbai Mountains