Abstract:

In order to investigate the limit factors that influence soil water infiltration, and increase the adjusting and controlling roles in rain run-off in urban green land, soil infiltration in different functional urban green areas and the soil properties including particle size distribution, bulk density, the total porosity and aeration porosity of soil samples collected from green lands in Hefei urban were investigated. Results demonstrated that in different urban green lands the clay particles were between 37.6% and 44.7% in all the soil samples; the soil bulk density ranged from 1.22 to 1.68 g/cm3, and the mean bulk density was higher than 1.40 g/cm3. The aeration porosity were ranged from 9.21% to 17.6%, and its mean level were in the order: residential area (14.1%)>municipal (13.9%)>park(13.7%)>campus (11.3%). The sharp decreases of soil infiltration were found in the first stage (0-40 min), slow decline in the second stage (40-90 min) and the stable stage (90-100 min) were tested by using the double rings infiltration methods. The mean soil infiltration velocity in different green areas expressed the following rules: park (2.42×10-5 m/s)>municipal (2.10×10-5 m/s)>residential area (0.62×10-5 m/s)>campus (0.56×10-5 m/s). About 21.1% of soil infiltration velocity was in the grade of medium fast and fast, and 78.9% of them in the medium slow and slow grade. Results from this study would provide critical facts for designing urban green lands and reducing urban non-point pollution through green land in Hefei.