Availability of Cu, Zn and Mn in soils: II.—Chemical extractability

Abstract

AbstractThe interrelationships of the amounts of Cu, Zn and Mn extracted with four chemical extractants of varying pH and buffering capacities, and as influenced by soil pH, organic matter, and available P, were evaluated. Regression equations using 0·1 N‐HCl, 0·01 M EDTA, and 0·005 M DTPA soil‐extractable fractions in conjunction with the soil properties for the estimations of total Cu, Zn and Mn in divergent Wisconsin soils are also given. The relationship of the Mg(NO3)2‐extractable fractions of the three elements to the above four fractions were better defined by quadratic than by linear equations. Exchangeable Zn had positive while exchangeable Mn had negative influence on exchangeable Cu in these soils with widely varying Cu supply. Both exchangeable Cu and Mn increased Mg(NO3)2‐extractable Zn, whereas exchangeable Cu depressed the Mg(NO3)2‐extractable soil Mn.