[Distribution characteristics of soil carbon and nitrogen in different land use types changed from urban wetlands.]

Five land use types of Longzihu wetland in Bengbu City, Anhui Province of China, including woodland, greenbelt, aquaculture land, cultivated land, shelter forest, were chosen as the research object. Through analyzing the content and allocation proportion of total organic carbon (TOC), total nitrogen (TN), particulate organic carbon (POC), particulate organic nitrogen (PON), as well as soil carbon nitrogen ratio (C/N) and soil particles component carbon nitrogen ratio (POC/TOC), soil carbon and nitrogen distribution characteristics were discussed under dif-ferent human disturbance intensities and modes. Results showed that TOC showed surface accumulation in woodland, aquaculture land and cultivated land, while it did not show significant variation in each soil layer of greenbelt and shelter forest. POC, TN and PON showed surface accumulation in all land utilization types. Greenbelt and shelter forest, being disturbed strongly by human activities, had higher POC allocation proportions, while aquaculture land and cultivated land, heavily interfered by human activities, had relatively lower POC allocation proportions which were commensurate with that of woodland. Woodland received less interference by human activities, so in addition to disturbance intensity, disturbance mode might be another important factor affecting POC allocation proportion. C/N decreased with the increase of soil depth in woodland, but C/N of greenbelt, cultivated land and shelter forest had no obvious changes along the soil profile. Soil depth had no significant impact on POC/TOC in the land use types except woodland and cultivated land.