Olsen's method, which is used for phosphorus detection method used in soil is

Solution(By Examveda Team)

Olsen's method, which is used for the phosphorus detection method used in the soil is all expected sodic soils.
The Olsen method is a chemical extractant (bicarbonate) that provides a reasonable estimate of the amount of plant-available P by measuring phosphate from the soil solution and exchange surfaces.
This procedure is suitable for all expected sodic soils, calcareous, alkaline, neutral and slightly acidic soils containing CaPO₄, since the calcium concentration in the solution is suppressed by the precipitation of CaCO₃, increasing PO₄ concentration in the solution.