Evaluation on Fertility of Urban Forest Soil in Nanjing

• 1、College of Forest Resource and Environment, Nanjing Forestry University

Abstract：Physical and chemical properties as well as enzyme activity of urban forest soil in different functional areas of Nanjing were analyzed. The result revealed that surface soil (0-20cm) had a high bulk density, low porosity and permeability. Soil texture was dominated by silt loam which accounts for 60.42%. The content of gravel is low in most of the soil samples. The type of soil was dominated by neutral and alkaline soil, and the pH value of unnatural forest soil were distinctly high compared with suburban natural forest soil. Soil organic matter and total nitrogen were low, CEC was high. Soil available potassium enriched, and soil available phosphorus enriched in unnatural forest soil but lacked in suburban natural forest soil. Hydrogen peroxidase activity in urban forest soils changed from 0.19 ml•g-1 to 0.37ml•g-1，with a average of 0.28 ml•g-1；Dehydrogenase activity changed from 3.91 ml•g-1 to 48.03 mg•g-1，with a average of 25.74 mg•g-1；Alkaline phosphatase activity changed from 5.29 mg•kg-1 to 25.70 mg•kg-1，with a average of 12.80 mg•kg-1；Cellulase activity changed from trace to 0.002 mg•g-1，with a average of 0.0015 mg•g-1；Hydrogen peroxidase, dehydrogenase and alkaline phosphatase were important indicators for indicating fertility of urban forest soil and all had significant relation with soil organic matter and total nitrogen.

Keywords： Nanjing city Urban forest soil Soil fertility quality Evaluation