Study on Soil Moisture Characteristics of Different Forest Vegetations in Jiulongshan, BeiJing

Soil moisture retention characters of different forest vegetations in Juilongshan were analysed by measurement of soil water characteristics in the field.The result showed there was a high power function correlation between the soil moisture content and the potential of soil water. The mathematical model is:θ=aSb.Soil moisture retention of different forest vegetations were ranged in order from better ones to poor ones as follows:schattenseite shrubland,schattenseite bare soil,schattenseite Pinus tabulaeformis forest soil, endroit shrubland, endroit bare soil,endroit Platycladus orientalis forest soil. Slope orientation and vegetation type are the main factors affecting the soil moisture retention. On the same slope orientation,soil moisture retention of shrub forest land was better than that of the high-forest land.In all the forest land, the soil moisture retention of superficial soil (0～20 cm) was better than that of subsurface soil (20～60 cm). On the same site,the soil factors influencing the soil moisture retention characters in medium and low suction range are soil structure, organic matter content and soil texture.