HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Geering, H. R. Articles by Hodgson, J. F. Search for Related Content PubMed Articles by Geering, H. R. Articles by Hodgson, J. F. Agricola Articles by Geering, H. R. Articles by Hodgson, J. F.

Micronutrient Cation Complexes in Soil Solution: III. Characterization of Soil Solution Ligands and their Complexes with Zn²⁺ and Cu²⁺¹

ABSTRACT

At least three groups of compounds were found to complex Zn²⁺ and Cu²⁺ in soil solution from the A horizon of a Williamson silt loam. A nondialyzable fraction of soil solution ligands had a poorly defined acid dissociation, pKa, ranging from 3 to 4.7. The dialyzable fraction had acid dissociation constants of 4.5 and 9.5, which were attributed to aliphatic and amino acids, respectively. The equivalent concentration of the nondialyzable acid fraction was only 1/40 that of the dialyzable fraction, but was more effective in complexing Zn and Cu in the soil solution. The average metal/ligand ratio was equal to unity in complexes of both the dialyzable and nondialyzable fractions with Zn²⁺ and Cu²⁺. Estimated, log₁₀ (average formation constants) of the nondialyzable-metal complexes were calculated on the basis of titratable acidity as 4.3 ± 0.1 and 5.5 ± 0.1 for Zn²⁺ and Cu²⁺, respectively.

¹ Contribution from the US Plant, Soil and Nutrition Laboratory, SWC, ARS, USDA, Ithaca, N.Y., in cooperation with the Department of Agronomy, New York State College of Agriculture, Ithaca.

² Research Associate and Soil Scientist, respectively. Second author is also Associate Professor at Cornell University.

Received for publication May 3, 1968. Accepted for publication July 31, 1968.