A sequential extraction method for phosphorus (P) from plant material involves : water, sodium bicarbonate, sodium hydroxide, and acid extractions, followed by residual P determination, allowing for the differentiation of P forms and providing insights into P bioavailability and cycling in ecosystems. The method requires sample preparation, extraction steps, and analysis using colorimetric assays, or ICP-OES, with considerations for phosphorus contamination and optimization of extraction conditions based on specific plant materials.