Use Of Bray-2 Test To Evaluate Available Phosphorus In Soils Treated With Phosphate Rocks For Oil Palm: A Review

Bray-2 test has been widely used to evaluate available P in acid soils treated with different phosphate rock (PR) sources for oil palm plantations in Malaysia and Indonesia. The review shows that Bray-2 test, which is a strong acid reagent, often overestimates available P in the soil compared with the actual P in soil solution from the dissolution of PR. Consequently, none or poor correlations between fresh fruit bunch (FFB) yield of oil palm and Bray-2 P have often been obtained. This problem occurs when comparing Bray-2 P from PR with that from water-soluble P (WSP) fertilizer such as TSP or comparing highly reactive PR with low-reactive PR. A new mixed cation-anion resin has been proven effective for evaluating available P from different types of P sources including PRs of varying reactivity and WSP for field crops. The resin method should be studied to test if it can be used to replace the current Bray-2 test to evaluate available P for oil palm.

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