Studies on Soil Dynamic under Pinus bungeana,Pinus tabulaeformis,Platycladus orientalis Plantation in the Western Suburb of Beijing

Permanent sample plots were located under plantations in the Western Suburb of Beijing.There are three plantation soil types for the sample plots: (1) eluvial cinnamon soil under Pinus bungeana plantation;(2) eluvial cinnamon soil under Pinus tabulaeformis plantation;(3) eluvial cinnamon soil under Platycladus orientalis plantation.Observation began in 1981 and ended in 1984.It has been found that the soil moisture content of the experimental plantation field were 10~15 mm in growth season.It belongs to the sub-arid-wet soil moisture regime.Annual mean soil temperature .was 13℃,belongs to the temperate soil temperature regime.Seasonal variation of soil moisture and temperature were evident,annual variation (1981~1984) were not evident.Seasonal variation of soil CO2 content in the experimental plantation field were evident,but annual variation (1981~1984) were not evident.The variations of different stands in the experimental plantation fields were not evident enough.