采用Hedley土壤磷的分级方法研究了我国几种典型土壤和长期定位试验肥料残留磷（积累态磷）的形态．并根据生物耗竭试验后不同级磷的减少讨论了各级磷的有效性．结果表明．即使在固磷能力很强的红壤上，积累态磷也大部分存在于可被作物利用的磷的形态中．这就是为什么磷肥的积累利用率高的基本原因． Hedley soil phosphorus grading method was used to study the morphology of residual phosphorus (accumulated phosphorus) in several typical soils and long-term experimental fertilizers in China. The effectiveness of phosphorus at all levels was discussed based on the reduction of different levels of phosphorus after the bio-depletion test. The results show. Even in red soils where phosphorus fixation is very strong, most of the accumulated phosphorus is found in the forms of available phosphorus. This is the basic reason why the accumulation and utilization of phosphate fertilizer is high.