Mehlich 3 extractant for determination of available B, Cu, Fe, Mn, and Zn in cryic Alaskan soils

Mehlich 3 extractable B, Cu, Fe, Mn and Zn, DTPA-TEA extractable Cu, Fe, Mn and Zn, and hot water extractable B were measured on three soils from factorial experiments with variable rates of B, Cu, Mn and Zn, and from two B rate and liming studies. Neither Mehlich 3 nor DTPA-TEA extractant predicted plant-available Cu or Fe. The inclusion of soil pH and organic matter slightly improved estimates of available B, Mn and Zn. Mehlich 3 extractable Fe was poorly related to DTPA-TEA extractable Fe. Copper extracted with Mehlich 3 was related to that extracted with DTPA-TEA; the inclusion of soil pH improved the relationship. Mehlich 3 extractable Mn and Zn were closely related to DTPA-TEA extractable levels. The correlation between Mehlich 3 and hot water B was significantly improved by including soil organic matter content. -from Authors