Assessment on Soil Quality of Different Stand Types in Wuhan Jiufeng National Forest Park

The evaluation of soil quality in urban forests is of great significance for the construction and sustainable management of urban forest vegetation. Five typical urban artificial forests (including Pinus massoniana forest, Liquidambar formosana forest, Quercus variabilis forest, coniferous and broad-leaved mixed forest, and evergreen broad-leaved mixed forest) were selected as the research objects in Jiufeng National Forest Park, Wuhan City. The differences of soil physical and chemical properties and their relationships among different stand types and soil layers were analyzed. The integrated soil quality indexes of different stand types were also evaluated. The results showed that the physical and chemical properties of urban forest soil in Wuhan are significantly influenced by stand types. The differences were significant at the pH value in 10～20 cm and >40 cm, organic matter and hydrolytic nitrogen in 20～40 cm and >40 cm, total nitrogen and total phosphorus in 0～10 cm, 10～20 cm, and 20～40 cm, and available phosphorus in 0～10 cm soil layers (P<0.05). Soil moisture content, soil bulk density, maximum water holding capacity, capillary water holding capacity, capillary porosity, total porosity, total potassium and available potassium in all of the four soil layers among different stand types also showed significant differences (P<0.05). The comprehensive ranking is as follows: coniferous and broad-leaved mixed forest > Liquidambar formosana forest > Quercus variabilis forest > evergreen broad-leaved mixed forest > Pinus massoniana forest. The soil quality of coniferous and broad-leaved mixed forest and the broad-leaved forests' are superior to the coniferous forest's, deciduous broad-leaved forest is superior to evergreen broad-leaved forest. Moderately increasing the proportion of deciduous broad-leaved plants in forest stands, managing and maintaining understory vegetation, and regulating soil acidity and alkalinity will be beneficial for improving the soil quality of urban forests in Wuhan.