Relationship between ammonium acetate‐acetic acid and morgan's solution for determining extractable P, K, Ca, and Mg in soils derived from calcareous glacial till

Abstract

Long filtration time, accumulation of salt residue on the atomic absorption or flame emission burner slot, and contamination of P and K in the sodium acetate are three problems encountered when using sodium acetate‐acetic acid or Morgan's solution (MS) for extracting P, K, Ca, and Mg from soil samples. Thus an ammonium acetate‐acetic acid (AA‐AA) solution was compared with MS for 144 soil samples which, although ranging in pH from 4.4 to 7.9, were all derived from calcareous glacial till. A highly significant linear correlation was obtained between the two methods for each of the four elements. Filtration time for the AA‐AA solution was 30–45 minutes shorter than that for MS. No salt residue accumulated on the atomic absorption burner slot when using AA‐AA. Because of these advantages, we have replaced MS with AA‐AA for samples analyzed in our laboratory.