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

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Si, B. C. Articles by de Jong, E. Search for Related Content PubMed PubMed Citation Articles by Si, B. C. Articles by de Jong, E. Agricola Articles by Si, B. C. Articles by de Jong, E. Related Collections Soil Hydrology Uncertainty Analysis Recharge

TECHNICAL REPORTS

Vadose Zone Processes and Chemical Transport

Determining Long-Term (Decadal) Deep Drainage Rate Using Multiple Tracers

Dep. of Soil Science, Univ. of Saskatchewan, Saskatoon, SK, Canada

^* Corresponding author (Bing.Si{at}usask.ca).

Received for publication January 14, 2007. The deep drainage rate is a critical hydrological parameter in understanding contamination mechanisms of soil and groundwater. Little research has been conducted on the temporal variations in deep drainage rate during the last century. The objective of this study was to determine the long-term deep drainage rate on a cultivated loamy soil in the Canadian Prairies. Three tracers were used: KCl applied in 1971, fallout tritium in 1963, and NO₃^– released during the initial cultivation of the field (1923). Two soil cores to a depth of 3.6 m were taken along a flat portion of the field, and soil Cl^–, ³H, and NO₃^– concentrations were measured as a function of depth. An additional four cores were taken for soil water content measurements between 2000 and 2003. Distinct peaks in the depth distribution of these three tracers were located at 1.27 m for Cl^–, 1.31 m for ³H, and 1.52 m for NO₃^–, 32, 40, and 80 yr after the application of Cl^–, ³H, and NO₃^–, respectively. The average deep drainage rates, calculated as the product of the estimated tracer velocity and volumetric soil water content below the active root zone, were 2.0 mm yr^–1 from the Cl^– tracer, 2.2 mm yr^–1 from ³H, and 2.5 mm yr^–1 from the NO₃^– tracer. Therefore, there was little temporal variability in the groundwater recharge over the eight decades that the field has been cultivated. The recharge rates are less than 1% of the mean annual precipitation (333 mm).

Abbreviations: MPA, mass per unit area • ZFP, zero flux plane