[Soil P availability in larch rhizosphere].

Soil samples were collected from the rhizosphere and non-rhizosphere of larch(Larix gmelini) stand by exfoliation method, and the variation of P concentration was analyzed. The results show that there was no significant difference between total P concentrations in the rhizosphere and the non-rhizosphere soil, while the concentration of available P in rizhosphere soil was significantly higher than that in the non-rhizosphere soil. The concentrations of available P in rhizosphere 12 years old and 40 years old larch rhizosphered by 12.6% and 23.4% respectively, indicating that larch roots had the effect of mobilizing soil phosphorus. The components of inorganic P in rhizospheric soil were different from those in non-rhizospheric soil. The concentration of O-P was lower, and the concentrations of Al-P, Fe-P, Ca-P, NH4Cl-P were higher in the rhizosphere. The pH of rhizospheric soil was lower than that of non-rhizospheric soil, but no further acidification was observed. There was no close relationship between pH variation and available P concentration in larch rhizosphere.