Evaluation Iron Oxide Impregnated Paper Strips (Pi) Used in Determining Available Phosphorus of Some Soils in Hamadan Province

Iron oxide-coated strips (Pi) can serve as a sink to continuously remove P from solution. In this way, probably, P extraction is analogous to P absorption by plant root. The objective of this study was to evaluate the iron oxide-coated paper strips to estimate the availability of soil P of corn (Zea mays) grown under greenhouse conditions in some soils of Hamadan Province. Sixteen soil samples with different physico-chemical properties were examined for available P by Olsen, Colwell, Mehlich1, 0.01 M CaCl2, AB-DTPA, 0.1 M HCl methods and two (Pi1, Pi2) Pi methods. Furthermore, the effects of two P levels ( 0 and 250 mg P Kg-1 soil) on the plant responses (P uptake, P concentration, and relative yield) were studied in the greenhouse experiment using 12 soil samples. The results showed that the amount of extractable P decreased in the order: 0.01 M Cacl2 < Pi2 < AB-DTPA < Pi1 < Olsen