Available Phosphorus Determination through Iron Oxide Impregnated Strip Paper's and the Comparison with Conventional Chemical Methods

Such ion-sink methods as FeO coated strips, (Pi), can adsorb and collect P from soil solution. Ion sink methods function similar to plant-root surface, adsorbing available P ions from the P pool in the soil. The objective of this study was to compare Pi test with Olsen, AB-DTPA, Bray 2 and Mehlich 2 methods to estimate the availability of soil P in alfalfa (Medicago sativa). Available P was detrmined through the above methods in 15 soil samples. Pot experiment was carried out in a randomized block design of two P levels (0 and 200 mg kg-1) plants being harvested in 3 cutting stages. The results indicated that the amount of P extracted through Pi method was significantly correlated with that in other chemical extractant methods. The results obtained from pot experiment revealed that in the first cutting, P uptake was found not to be significantly correlated with P extracted through either Pi or other chemical methods. In the 2th and 3 th cutting¬s P uptake along with other plant indices were significantly correlated with P extracted through Pi method as well as through other chemical methods with Bray2 method being an exception. The results finally demonstrated showed that Pi method can be equally employed for estimating available P in alfalfa plant, as the other chemical methods.