Abstract: In order to understand the spatial pattern of organic carbon accumulated in urban soils, 48 different age green spaces in Hangzhou City were selected,
 and their soil total organic C, particulate organic C, black C, microbial biomass C, and metabolic quotient (ratio of basal respiration to microbial biomass) w
ere determined. Once the anthropogenic activities ceased or the soilformation conditions were stable, the urban soils developed toward a certain direction, similar to other terrestrial ecosystems. With the increase of green space age, the accumulation of soil organic C, particulate organic C, microbial biomass C and b
lack C increased, while the soil bulk density and metabolic quotient decreased, indicating that as one of the soilformation factors, time played an important
role in the spatial variation of the physical, chemical, and biological properties of urban soils. It was recognized that with the cessation of human disturbance
 and the increase of green space age, the impact of urbanization on urban soil properties was gradually weakened.

Key words: Loess Plateau, Small watershed management, Ecological reconstruction, Scaling and complementarity