Soil sample P test result by Mehlich 3 and by Olsen extraction
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Some samples from the MLSN dataset were tested for P by both Mehlich 3 and Olsen extractants. This chart shows the relationship between the P extracted by the two methods, across a range of soil pH values. Mehlich 3 always extracts more P from a soil sample than does Olsen. That relationship between P extracted by Mehlich 3 and Olsen extractants is similar across low, medium, and high soil pH in these samples.
