Abstract: Understanding changes in soil phosphorus concentration is critical to predict the influence of longterm environmental change on forest ecosystems. By measuring total phosphorus and available phosphorus concentrations in rhizospheric soil of Pinus koraiensis and Quercus mongolica in the sixthyear nitrogen and precipitation manipulation experiment, we intended to study the influence of longterm nitrogen deposition and precipitation variation. The results showed that longterm nitrogen fertilization significantly increased the total phosphorus concentration in rhizospheric soil by 7.4%-10.9%, and the influence of tree species on total phosphorus concentration in rhizospheric soil was not significant. Longterm nitrogen fertilization significantly increased the available phosphorus concentration in rhizospheric soil of P. koraiensis and Q. mongolica by 25.1% and 32.4%, respectively. The available phosphorus concentration in rhizospheric soil of Q. mongolica was 31.8%-84.1% higher than that of P. koraiensis. The reduction in precipitation had no significant effects on both total phosphorus and available phosphorus concentrations in rhizospheric soil.

Key words: Pinus tabuliformis, LPJ-GUESS model, climate change., net primary productivity