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 Qafoku, N. P. Articles by Radcliffe, D. E. Search for Related Content PubMed Articles by Qafoku, N. P. Articles by Radcliffe, D. E. Agricola Articles by Qafoku, N. P. Articles by Radcliffe, D. E.

Anion Transport in Columns of Variable Charge Subsoils: Nitrate and Chloride

Dep. of Crop and Soil Sciences, The Univ. of Georgia, Athens GA 30602-7272.

^* Corresponding author (qafoku{at}arches.uga.edu).

ABSTRACT

Acid variable charge subsoils exhibit a positive charge, which retards the passage of anions through the soil profile. The objective was to study the NO^–₃ adsorption isotherms and the effect of changing the subsoil positive charge on NO^–₃ and Cl^– retention, estimate NO^–₃ and Cl^– retardation in different subsoils, and quantify relationships between transport and adsorption parameters. Subsoils from different subtropical and tropical areas were used in column experiments. Four lime treatments and four leaching solutions were used to create different anion exchange capacities (AECs) in subsoils. In the Cecil subsoil (Fine, kaolinitic, thermic Typic Kanhapludult), NO^–₃ isotherms were linear between 5 and 30 mmol NO^–₃ L^–1. When forced through the origin, an L-curve NO^–₃ isotherm was observed at native and low soil pH. The NO^–₃ adsorption was largely affected by the changes in both pH and concentration of the leaching solution. Other variable charge subsoils have varying capacities to retard anions, which is reduced when either soil pH or leaching solution concentration is increased. Both parameters equally reduce the distribution coefficient K_d and the retardation coefficient R. The AEC correlates closely with R and K_d. As a result, AEC can be successfully used in the solute transport models to estimate K_d or R without measuring it to correct for the NO^–₃ retardation.

This article has been cited by other articles:

				S. Hyun, L. S. Lee, and P. S. C. Rao Significance of Anion Exchange in Pentachlorophenol Sorption by Variable-Charge Soils J. Environ. Qual., May 1, 2003; 32(3): 966 - 976. [Abstract] [Full Text] [PDF]

				N. P. Qafoku and M. E. Sumner Adsorption and Desorption of Indifferent Ions in Variable Charge Subsoils: The Possible Effect of Particle Interactions on the Counter-Ion Charge Density Soil Sci. Soc. Am. J., July 1, 2002; 66(4): 1231 - 1239. [Abstract] [Full Text] [PDF]