Characteristics Of Soil, Litter And Biodiversity In Over-logged Forest Stands Of Quercus Mongolica In Northeastern China

Quercus mongolica, one of the most important oak hardwood tree species, is widely distributed in Northeast China and forms typical Quercus mongolica forest, which plays an important role in boreal forest succession and development. Forest stands of Quercus mongolica in the over-logged forest area in northeastern China were selected to study characteristics of soil nutrients, soil enzyme activities, soil organic carbon (SOC) density, biodiversity and forest litter with descriptive statistical analysis, correlation analysis, principal component analysis and analysis of variance.The results were showed as follows:1)The mean soil nutrients content was:soil organic matter 26.81 g/kg, total N 0.54 g/kg, alkaline hydrolysis N 68.94 mg/kg, total P 0.32 g/kg, available P 7.23 mg/kg, total K 30.42 g/kg, and readily available K 172.46 mg/kg, respectively. The soil was acid with pH value of 5.54. Soil total K and readily available K contents were rich, and the other soil nutrient contents were in the lower level.2)With increasing soil depth, SOC content and density decreased significantly. The mean SOC content of Quercus mongolica forest was 15.55 g/kg and SOC density to the depth of 60 cm was 10.09 kg/m2. SOC content and density had very significant positive correlations with total N and P as well as available P and K.3)With increasing soil depth, soil urease and acid phosphatase activities decreased significantly, which, to some extent, had very significant positive correlations with soil water content, but negative correlations with soil bulk density. Soil enzyme activities had very significant positive correlations with total N and P content.4)The Shannon-Wiener index and Simpson index of the herb layer was higher than tree layer and shrub layer, and there was not a big gap between the Shannon-Wiener index and Simpson index of the herb layer, indicating that the herb layer species were abundant and equally distributed. There existed certain correlations between the biodiversity of the tree layer and herb layer and soil physico-chemical properties, and their correlations with soil pH, available N and total P content reached significant or very significant levels. In the study area, the soil physico-chemical properties could affect the biodiversity to a certain degree.5)The standing crop of the litter in the study area was 11.20 t/hm2. In the un-decomposed and the duff layers, the water-holding capacity of the litter was 2.01 t/hm2 and 4.37 t/hm2, respectively. The water-holding capacity increased with the standing crop of the litter. In addition, the nutrient contents of the litter increased with the degree of decomposition except C. The standing crop, water-holding capacity, and nutrient contents of the litter had certain correlations with soil physico-chemical properties.