Abstract:Effects of fertilizer application of P and PK on soil properties and foliar nutrients of young stands of loblolly pine(Pinus taeda) and slash pine (P.elliottii) were studied during 1991～1995 on the site of red earth derived from phyllite in the hilly land of Jingdezhen City of Jiangxi Province. The results showed that: (1)Rapidly available P content of soil increased while organic matter and other nutrients decreased in the soil of both stands after the fertilization of P and PK; P application could facilitate the mineralization of organic matter and the absorption of N. (2) P and PK application could increase the numbers of bacteria, fungi and cellulosedecomposing bacteria but reduce actinomyces in the soil of slash pine and stimulate aerobic nitrogenfixing bacteria and phosphobacteria at the early stage of fertilization while inhibit at the later stage. (3) P and PK application could also improve activities of soil urease and catalase, and inhibit soil phosphatase at the early phase of fertilization but release its activity at the latter phase; sucrase activity could be improved by P application while inhibited by PK. (4) P and PK application could significantly increase Ca and Mg after two years from fertilization but reduce N content in the needle of slash pine, and there was no significant effect on P and K content in the needles.