Abstract:Soil phosphorus is considered the key factor for restricting the productivity of plantations in south subtropical China. However, little information is available about the change in soil phosphorus fractions and sorption characteristics of different species plantations in this area. The content of phosphorus fractions and phosphate adsorption properties in different soil layers (0-20, 20-40 and 40-60 cm) were analyzed under exotic fast-growing eucalyptus plantation and typical native species (Pinus massoniana, Castanopsis hystrix) plantations in the Experimental Center of Tropical Forestry of Chinese Academy of Forestry located in Pingxiang City, Guangxi. The results revealed that organic phosphorus (Po) which accounted for 46.25%-71.58% (91.51-257.45 mg/kg) of total phosphorus (TP), was the main form of TP in the three plantation soils. The contents of soil TP, Po and inorganic phosphorus (Pi) in eucalyptus plantation were obviously lower than those in Pinus massoniana and Castanopsis hystrix plantations. Meanwhile, the content of soil labile organic phosphorus (LO-P) was significantly higher in eucalyptus plantation than in the two native species plantations, while the contents of soil Al-P, Fe-P, O-P and Ca-P were lower than in the two native species plantations. In addition, the potential maximum phosphorus adsorption capacity (Qm) in eucalyptus plantation was lower than that in the two native species plantations, while the degree of phosphate saturation (DPS) was higher than in the two native species plantations. Therefore, in terms of soil phosphorus supply and adsorption property, Pinus massoniana and Castanopsis hystrix could be superior to eucalyptus as the afforestation tree species in this region.