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 Rhoades, J. D. Articles by Reed, M. J. Search for Related Content PubMed Articles by Rhoades, J. D. Articles by Reed, M. J. Agricola Articles by Rhoades, J. D. Articles by Reed, M. J.

The Effect of Soil-Mineral Weathering on the Sodium Hazard of Irrigation Waters¹

ABSTRACT

The extent to which the release of solutes from soil-mineral weathering processes changes the composition of applied irrigation waters has been evaluated for six arid-land soils. Soil samples were packed in plexiglas permeameters and pretreated to remove readily soluble organic matter, to minimize subsequent microbial activity, and to equilibrate the soil exchange-complexes with the irrigation waters. Soil solutions were displaced from the nearly saturated columns and analyzed at biweekly intervals until a steady composition was attained. The effluent solutions were 3 to 5 meq/liter higher in total salt content than the applied waters. The gains were accounted for primarily by Ca + Mg and HCO₃ ions. The net effect of these changes in solution compositions was a 30 to 90% reduction in the SAR values of the applied solutions. The SAR reductions were greatest for the waters of lower salt concentrations, but were significant even for waters containing as much as 15 to 20 meq of salt per liter. This phenomenon reduces the Na hazard expected with certain irrigation waters, and should be considered in water-quality evaluation.

¹ Contribution from U. S. Salinity Laboratory, Soil & Water Conservation Research Division, ARS, USDA, Riverside, Calif., in cooperation with the 17 Western States and Hawaii. Presented before Div. S-2, Soil Science Society of America, Nov. 9, 1967, Washington, D.C.

² Soil Chemist and former Research Assistants, respectively, U. S. Salinity Laboratory, Riverside, Calif.

Received for publication December 5, 1967. Accepted for publication April 23, 1968.