Soil Quality Of Different Man-Made Forest Types In Lower Mountain Area, Beijing

By selected 3 kinds of man-made coniferous forests (Platyclatus orientalis, Pinus tabulaeformis, Pinus bungeana) and 5 kinds of man-made broadleaved forests(Acer mono, Quercus variabilis, Quercus dentate, Robinia hisqida,Cotinus coggygria) which located in Beijing Xishan experimental forest farm, the soil physical and chemical properties, soil enzyme activity, plant diversity under different forest types, and the correlation among them were studied with field surveying and laboratory analyzing. The research results obtained forest soil characteristics under different man-made forest in lower mountain area will provide some basis for the soil health management of plantation in Beijing.The results showed (1) Some differences in different forest types were further examined by analyzing the soil physical properties, in general, broadleaved forest were more advantageous than coniferous forests in improving soil physical properties. (2) The pH value ranged from 4.68 to 6.27, and it belonged to acid or acidic soil. The largest difference of soil pH value under different forest types was observed in surface layer. The soil pH value increased with increasing soil depth in soil vertical profile. The soil nutrient concentration such as of soil organic matter, soil nitrogen, soil NH4+-N, soil available phosphorus and soil available potassium in 0-20cm layer were the highest followed by the 20-40cm, and lowest in 40-60cm layer. There were no significant differences in soil NO3--N between different soil depths. The soil NH4+-N concentration in surface layer was higher than soil NO3--N. The lower concentration soil available phosphorus may be a factor to limit forest health, whereas soil available potassium concentration of different forest types is greater than 116 mg/kg. (3) There were significant differences in soil enzyme activity between different forest types. Soil urease activities in surface layer were commonly in 0.2 mg/g. The soil urease activities under Platyclatus orientalis and Robinia hisqida were higher than the other forest types. The differences in soil catalase activities under different forest types were obvious. The order from high level to low level was according to Platyclatus orientalis>Pinus tabulaeformis>Pinus bungeana> Quercus dentata>Robinia hisqida. Soilβ-glucosidase activity under Platyclatus orientalis was 7.25mg/kg, whereas those was lower under Pinus tabulaeformis and Pinus bungeana, it ranged from 1.96mg/kg to 3.4mg/kg. There were obvious differences in soil acid phosphatase activity and alkaline phosphatase activity under different forest types. An order of succession of soil acid phosphatase activity was Cotinus coggygria>Pinus tabulaeformis1>Quercus dentata>Robinia hisqida, and other forest types were less than 0.15 mg/g. The order of soil alkaline phosphatase activity followed the rule Platyclatus orientalis1>Platyclatus orientalis2>Quercus variabilis>Acer mono>Cotinus coggygria>Robinia hisqida>Quercus dentata>Pinus bungeana>Pinus tabulaeformis1>Pinus tabulaeformis2. (4) Under different forest types, the plant species, quantity and distribution uniformity in herb layer were lower than those in shrub layer.