Abstract: Quantifying changes in soil physicochemical properties of forest ecosystems is important for forest regeneration. In this study, four vegetation types including grassland, shrub land, Larix principisrupprechtii Mayr. pure forest, and L. principisrupprechtii and Betula platyphlla Suk. mixed forest were selected as the research object in Haodifang Forest Farm in Taiyue, Shanxi Province. Soil samples were collected at depths of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm, to analyze their physicochemical properties. The soil bulk density and pH value increased with the increase of soil depth, while the opposite is true for the soil water content. The soil water content decreased in the following order: L. principisrupprechtii and B. platyphlla mixed forest > grassland > L. principisrupprechtii pure forest > shrub land. The soil bulk density decreased in the order of shrub land > L. principisrupprechtii and B. platyphlla mixed forest > L. principisrupprechtii pure forest > grassland. The pH value ranked as L. principisrupprechtii and B. platyphlla mixed forest > L. principisrupprechtii pure forest > shrub land > grassland. The soil organic matter and total nitrogen (TN) presented a decreasing trend with the increase of soil depth and there were significant differences among different soil layers. There were no significant differences of total phosphorus (TP) and total potassium (TK) among different soil layers. Among the four vegetation types, the contents of soil organic matter, TN and TP in grassland were remarkably higher than that in the other three vegetation types. The TK content in shrub land was higher than that in the other three vegetation types. There was a significant positive correlation between TN and soil organic matter. Soil bulk density was negatively correlated with soil water content, organic matter and TN, and pH value was negatively correlated with soil organic matter, TN and TP.

Key words: hydrological frequency., hydrological gene, evolution principle, moment, non-consistency