Abstract:In this paper,the main results show that the seedlings of pine,China fir and cypress can use 32P labelled iron phosphate as a phosphorous source.Although a relatively small amount of phosphorous is absorbed from iron phosphate,both the amounts of phosphorous absorbed by the plants,from 32P-labelled calcium superphosphate and iron phosphate are found to be increasing constantly during two experiment period in 1984—1985.The ratio of the amounts of iron phosphorous to calcium superphosphate absorbed by cypress reached 10.5%,at the 93th days in 1985.The results indicate that even if the soluble phosphate change into insoluble iron phosphate in soil,the latter still can be used by these plants.