岷江上游本地种油松和外来种辐射松造林对土壤磷的影响

通过测定岷江上游16年生本地种油松和外来种辐射松人工林下不同土壤层次中各形态磷素含量以及磷酸酶活力,阐述两种林分对土壤磷素含量及其分布的影响.结果表明,在各个土层中,两种林分下的土壤含水量、pH值、有机碳的含量以及微生物生物量磷均无显著差异.在0～20cm土层中,油松林与辐射松林土壤全磷、Al-P、Fe-P、Ca-P含量以及磷酸酶活力均无显著差异,而油松林土壤有效磷和有机磷显著高于辐射松林;在20～40cm土壤中,油松林土壤全磷、有效磷、有机磷、Al-P、Fe-P含量与辐射松林差异不显著,油松林土壤Ca-P含量、酸性磷酸酶和中性磷酸酶活力显著高于辐射松林;在40～60cm土壤中,油松林土壤除中性磷酸酶活力与辐射松林的差异不显著外,其余各形态磷素含量和酸性磷酸酶活力变化与20～40cm土壤中的一致.此外,随土壤深度的增加,两种人工林土壤各形态磷素含量、磷酸酶活力都呈降低的趋势.单从土壤磷的状况看,油松林土壤中磷素含量高于辐射松林.

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 0-20 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 20-40 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 40-60 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.