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 Espinoza, W. Articles by Adams, R. S. Search for Related Content PubMed Articles by Espinoza, W. Articles by Adams, R. S., Jr. Agricola Articles by Espinoza, W. Articles by Adams, R. S.

Charge Characteristics and Nitrate Retention By Two Andepts from South-Central Chile¹

ABSTRACT

Charge characteristics of two Andepts, or volcanic-ash-derived soils, from south-central Chile were studied using a combination of nitrate retention, pH dependent cation exchange capacity and pH titration curves. Nitrate retention was determined by washing the soil with KNO₃ solutions having the appropriate concentration and pH and determining the amount of nitrate adsorbed. Net surface charge was determined from potentiometric titration curves conducted using a batch technique.

Results show that both soils have a complex mixture of pH dependent and permanent charge surfaces. The maximum pH dependent charge is in the range of 15 to 20 meq/100g at either very low or very high pH and high electrolyte concentration. The permanent negative charge is in the range of 45 meq/100g and is apparently the result of ion substitutions and lattice vacancies in X-ray amorphous oxides and hydrous oxides rather than 2:1 type clay minerals.

¹ Paper no. 8920, Scientific Journal Series, Minnesota Agric. Exp. Sta., Univ. of Minn., St. Paul, Minn. 55101.

² Former Research Assistant and Professors of Soils, respectively. Department of Soil Science, Univ. of Minnesota, St. Paul, Minn. 55101.

Received for publication December 2, 1974. Accepted for publication April 22, 1975.