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 HighWire Citing Articles via Google Scholar Google Scholar Articles by McLean, E. O. Articles by Post, G. J. Search for Related Content PubMed Articles by McLean, E. O. Articles by Post, G. J. Agricola Articles by McLean, E. O. Articles by Post, G. J.

Aluminum in Soils: III. A Comparison of Extraction Methods in Soils and Clays¹

ABSTRACT

Samples of eight Ohio soils initially representing a wide range of extractable Al were moist-equilibrated for 3 months with increasing increments of both H₂SO₄ and Ca(OH)₂. Al was then extracted, using five salt solutions. Previously dialyzed bentonite, Putnam, and illite clays were extracted of their accumulated (and added) Al by direct treatment with salt solutions and by removal with cation-exchange resin (Dowex 50-8X, 20 mesh).

With low soil pH, NaCl, BaCl₂, and NH₄OAc at pH 4.8, all extracted comparable amounts of Al from the initialy more acid soils. However, soils less highly weathered initaly but made acid with H₂SO₄, released more Al to BaCl₂ than NH₄OAc at pH 4.8. With soil pH values above 5, more Al was removed by NH₄OAc at pH 4.8 than either NaCl or BaCl₂. Relatively little Al was obtained by extracting with either NH₄OAc at pH 7.0 or triethanolamine + BaCl₂ (Mehlich) solution regardless of soil pH. On the basis of extractability and solubility of Al and the possible effects on clay crystal stability, NH₄OAc at pH 4.8 appeared to be superior as an extractant to the unbuffered neutral salts and to those buffered at pH 7.0 or above.

The extractable Al appeared to be largely exchangeable, since the amounts removed did not exceed the CEC of the soils whether 0.4 to 1.2 symmetry (S) concentration of H₂SO₄ was added, or 13 to 28 S of AlCl₃ were equilibrated with the soils.

NH₄OAc at pH 4.8, NaCl, and BaCl₂ all extracted comparable amounts of Al from the acid clays and the resin after contact with the clays. In clays without Al added, more Al was extracted from Putnam with salt solutions than from the other clays; but less was extracted from it with resin. In contrast, much more Al was removed with resin from illite than from the other clays, and much more than with salts. The contents of extractable Al in bentonite and Putnam clays prepared from H-resin and Ca-resin increased with time but continued essentially equal in value, whether it was an H- or Ca-clay.

The relative amounts of Al obtained from the resin by the various extractants depended upon the clay with which it had been equilibrated. Symmetry values for various cations showed the relative bonding of the cations by the resin was Al > Ca Ba > K > Na NH₄ > H.

¹ Contribution from the Department of Agronomy, Ohio Agr. Exp. Sta. Presented before Div. II, Soil Science Society of America, Lafayette, Ind., Aug. 6, 1958. Published with the permission of the Director of Ohio Agr. Exp. Sta. as Journal Article No. 100-58.

² Professor, Assistant Professor, and Research Assistant, respectively, Ohio State University and Ohio Agr. Exp. Sta.

Received for publication November 7, 1958. Accepted for publication December 10, 1958.

This article has been cited by other articles:

				R. W. Heiniger, R. G. McBride, and D. E. Clay Using Soil Electrical Conductivity to Improve Nutrient Management Agron. J., May 1, 2003; 95(3): 508 - 519. [Abstract] [Full Text] [PDF]