Effects of different succession stages of broad-leaved Korean pine forest on soil phosphorus fractions

In order to explore the differences of soil phosphorus fractions in different forest community succession stages and different soil depths in broad-leaved Korean pine forest, the soil of broad-leaved Korean pine forest ( natural Betula costata secondary forest, secondary broad-leaved forest, secondary coniferous and broad-leaved mixed forest and original broad-leaved Korean pine forest ) in four different succession stages in Xiaoxing 'an Mountains was taken as the object to analyze the effects of different succession stages and different soil depths ( 0-10, 10-20, 20-40 cm ) on soil phosphorus fractions ( total phosphorus, available phosphorus, organic phosphorus and inorganic phosphorus ). The findings demonstrate that: with the progress of forest community succession, soil total phosphorus, available phosphorus, organic phosphorus, inorganic phosphorus, active organic phosphorus, moderately active organic phosphorus, Al-P and Fe-P showed a trend of first decreasing and then increasing, while moderately stable organic phosphorus, highly stable organic phosphorus, O-P and Ca-P showed a trend of first increasing and then decreasing. The contents of available phosphorus, moderately active organic phosphorus and Fe-P did not decrease significantly with the change of soil layer, and the content of Ca-P increased with the deepening of soil layer. The contents of total phosphorus, organic phosphorus, inorganic phosphorus, active organic phosphorus, moderately stable organic phosphorus, highly stable organic phosphorus, Al-P and O-P decreased with the deepening of soil layer.