Abstract: Aiming to understand soil phosphorus status of plantations in typical black soil region of Northeast China, the topsoil (0-10 cm) phosphorus fractionations and its availability were examined in four soil and water conservation plantations dominantly composed of Larix gmelini, Fraxinus mandshurica, Pinus sylvestris var. mongolica and Populus nigra var. italica × P. cathayan, respectively. The results showed that total P, OlsenP and the concentration of different P fractionations in F. mandshurica and P. nigra var. italica × P. cathayan plantations were significantly higher than that of the other two coniferous plantations. Organic P was the major fractionation in the four plantations’ topsoil, and sodium hydroxide extractable organic P (NaOHP_o) representing moderately
labile organic phosphorus was predominant, which accounted for 58.9% of total P. The contents of H₂OP_i and NaHCO₃P which were more labile to plant were lower, only accounting for 1.2% and 6.6% of total P, respectively. Except for NaHCO₃P_o, all the other P fractions of four plantations correlated with each other, and they also had significant correlations with soil organic matter, total P, OlsenP. Compared with the coniferous plantations, the broadleaf plantations presented higher availability of phosphorus.