Abstract

                                Available P extracted by different extractants viz.. Oisen. Bray No. 1, Bray No. 2. Truog. Williams, Mehlich. Dyer, Morgan. Fraps and Iso:opic exchange method were related to the different forms of soil P viz.. Saloid-P, Al-P. Fe P and Ca-P. Stepwise regressions have been adopted to assess the contribution of the different forms of P to the available P extracted by the above methods. The results have shown that Al-P was the prime source of P for plant up take and Bray No. 1 extractable P. The Ca-P fraction also significantly contributed to the P uptake by plants. Fe-P was the chief source of Olsen's P and isotopic exchangeable 32P. The greatest contribution in the variation of Bray No. 2 and Truog extractable P was from Ca-P. Al-P and Fe-P also significantly contributed to the available P extracted by the above two methods.

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