New Study Reviews Mehlich-3 Extractant

University fertilizer recommendations for Ohio, Indiana, and Michigan (Tri-State) are currently based on the Bray-P1 extractant for phosphorus and the ammonium acetate (AA) extractant for cations. These fertilizer recommendations are currently being revised, and will use the Mehlich-3 soil test extractant as the standard for both phosphorus and potassium. A recently released collaborative research study affirmed that Mehlich-3 phosphorus correlates well with Bray-P and Mehlich-3 cations correlate well with ammonium acetate cations, specifically for soils in the Tri-State region.

A&L Great Lakes Laboratories has been using Mehlich-3 extractant since the early 90's with internally developed conversion equations to report Bray P1 and ammonium acetate values for use with established university fertilizer recommendations. Most production soil laboratories use Mehlich-3 so that phosphorus and cations can be obtained with a single laboratory process.

The agronomy staff at ALGL has been closely following revisions to the Tri-State fertilizer recommendations, and have been working to prepare for the transition to directly reporting Mehlich-3 data upon customer request. If you have any questions, please call your ALGL agronomist to discuss this further. To learn more about how the Mehlich-3 extractant compares to the traditional extractants, you can read the research article here.