Abstract: The tracing study with ³²P isotope shows that the supply of phosphorus in topsoil is insufficient and the amount of available phosphorus in Aw soil is fairly lack. The utilization rate of phosphorus fertilizer in topsoil ranges from 6. 09 to 12. 35% and that in Aw soil is 13% or so. Application of organic fertilizer can increase the content of Olsen P in albic soil and mobilize potential phosphorus. Fertilizing feces is the best way to mobilize the potential phosphorus in soil. Olsen P is the reliable index to evaluate the phosphorus fertility of albic soil.

Key words: ³²P isotope tracing, Albic soil, Phosphorus utilization rate, Vitex negundo var heterophylla, water source, IsoSource model, Platycladus orientalis, hydrogen and oxygen stable isotopes, precipitation events