Iron oxide-coated strips can serve as a P sink to continuously remove P from solution. In this way, P extraction is analogous to P absorption by plant roots. Because the relationship between soil P sorption capacity and P extraction by the Fe oxide-coated strips can affect the interpretation of the P test values, it needs to be examined. The effectiveness of the Fe oxide-coated strips in extracting sorbed P, and its relationship with soil P sorption capacity and with the commonly used NaHCO3P test, were evaluated in acidic soils amended with varying amounts of P. Both the Fe oxide strip and NaHCO3P tests were correlated with corn (Zea maysL.) dry matter yields to determine their relative effectiveness in describing plant growth response to increased P availability in soils. Iron oxide strip-extractable P, like NaHCO3-extractable P, increased with increasing amounts of P added to the soils. The recoveries of sorbed P by the two tests were similarly affected by the P sorption capacities of the soils at a solution P concentration of 9.7 X 10−6Mor at a constant P addition of 20 mmol kg−1, which explains the close correlation between the two tests (R2= 0.85,P< 0.001). The Fe oxide strip-extractable P reflected more appropriately an intensity index, rather than a quantity index, in the characterization of soil P availability. Decreased P extraction by the Fe oxide strips at high ionic strengths indicated that desorption of sorbed P from soil limited P extraction by the Fe oxide strips and that maintaining similar ionic strength is important in assessing P availability among diverse soils. Both the Fe oxide strip- and NaHCO3-P tests correlated well with corn yields, tissue P concentration, and P uptake. The Fe oxide strip P test did not seem to have much advantage over the NaHCO3-P test in describing corn response to increased P availability in the soils; however, the Fe oxide strips can be stored easily for later analysis or sent to centralized locations for P determination, if necessary