A modification of childs’ field test for ferrous iron and ferric-organic complexes in soils

Abstract

A modification to Childs' field test for water-soluble and exchangeable ferrous iron in soils is described. To prevent redox decomposition of ferric-organic species, which is induced by the reagent �,�' -dipyridyl, a mixed NTA (nitrilotriacetic acid)-�,�-dipyridyl reagent at pH 7 is recommended.