Effects of native Pinus tabulaeformis and exotic Pinus radiata afforestation on soil phosphorus in the upper reaches of Minjiang River

This paper examined the contents of different phosphorus (P) pools and phosphatase activity in different soil layers under exotic Pinus radiata (PR) plantation and adjacent native Pinus tabulaeformis (PT) plantation. Results showed that there were no significant differences in soil total organic carbon (TOC),soil moisture content (SMC),pH and soil microbial biomass phosphorus (SMBP) in each soil layer between the two plantations. In the 020 cm depth soil,the contents of available phosphorus (AP) and total organic phosphorus (TPo) were significant higher in the PT plantation than the PR plantation,while in the 2040 cm depth soil,the contents of Ca-P,acid and neutral phosphatase activities were significant higher in the PR plantation than the PT plantation. In the 4060 cm depth soil,the PT plantation had significantly higher Ca-P and acid phosphatase activity than the PR plantation. In addition,with the increasing soil depth,the contents of different P pools and phosphatase activity decreased in both plantations. These results confirmed that the P content in the PT plantation was higher than in the PR plantation. Therefore,in terms of the supply of soil P,the PT could be superior to the PR as the tree species selection for the afforestation program in this region.