Abstract：In order to manage larch plantations scientifically, improve its soil quality continually and raise stand productivity, soil acidity change of larch plantations at different development stages and their relationship between active acidity (pH value), exchange acidity, hydrolytic acidity and various types of inorganic phosphorus were studied in mountainous area of eastern part of northeastern China. The results showed that, with stand age increasing, active acidity (pH value) in rhizosphere soil decreased continually, but exchange acidity, exchangeable aluminium increased obviously, their correlation coefficient between Ca-P, O-P, and total hydrolytic acidity in rhizosphere soil, respectively, decreased, that between Fe-P, exchange acidity, and exchangeable aluminium respectively increased. The change of active acidity and total hydrolytic acidity in rhizosphere soil greatly influenced Al-P, especially in young stand, near mature stand and mature stand stages, their correlation between active acidity,total hydrolytic acidity, and Al-P respectively, reached significant level or highly significant level. Ca-P change in rhizosphere soil was mainly influenced by active acidity in rhizosphere soil;There was strong correlation between Fe-P and total hydrolytic acidity in rhizosphere soil during various age stages. O-P in rhizosphere soil decreased when exchange acidity and total hydrolytic acidity increased. There was not significant correlation between soil acidity and various forms of inorganic phosphorus in non-rhizosphere soil, respectively.
2005, Vol. 3 
