Exchangeable Ca, K, Mg, Na (and Mn)

by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES)

Base cations are extracted by shaking 3 g of air dried soil in 30mL of 1 M NH4OAc (pH 7) for 30 min. Extracts are centrifuged, and the supernatant is decanted and analyzed by ICP-AES.

(See Method References No. 30 & 21)