Acid-Fluoride extracts for Soil Phosphorus (Bray's):



Weigh 5g of sample into an extraction container, and pour in 25ml of extracting solution. Shake for 1 minute and filter the contents through Whatman No. 42 paper. Fill "Alpkem" sample cups with filtrate. Samples are ready for analysis.

If you are in a "field" situation, after shaking you can let the samples settle. Then pipet of a portion from the top of the extraction container into a sample cup.

Note: The amount of soil, extracting solution and shaking time can all vary to suit the P content of your soil. Just be consistant with your samples.

Dickman and Bray (1940)
Bray and Kurtz (1945) Determination of total, organic, and available forms of phosphorus in soils. Soil Sci. 59:39-45

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