The measurement of soil cation exchange properties using the single extraction, silver thiourea method - an evaluation using a range of New Zealand soils

Abstract

The measurement of soil cation exchange properties using a single extraction with 0.01 M silver thiourea (AgTU) was investigated using a range of New Zealand soils. There were no differences in the amounts of cations extracted by leaching or 16 h shaking and at least 90% recovery of calcium, magnesium, potassium and sodium was obtained after 1 h shaking. AgTU extracted similar amounts of aluminium to 1 M potassium chloride but approximately twice as much manganese. CEC values obtained by AgTU extraction agreed well with those obtained by Gillman's method. CEC determined by measuring the silver remaining in solution after AgTU extraction was found to be accurate and rapid.