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

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Casey, F.X.M. Articles by Logsdon, S.D. Search for Related Content PubMed Articles by Casey, F.X.M. Articles by Logsdon, S.D. Agricola Articles by Casey, F.X.M. Articles by Logsdon, S.D.

Comparing Field Methods that Estimate Mobile–Immobile Model Parameters

^a Dep. of Agronomy, Iowa State Univ., Ames, IA 50011 USA
^b USDA-ARS, National Soil Tilth Lab., 2150 Pammel Dr., Ames, IA 50011 USA

View larger version (80K): [in a new window]   Fig. 1 A diagram of the soil sampling scheme beneath the tension infiltrometer. The soil sampled immediately after the tracer application was used to estimate im and with the Jaynes et al. (1995) method, and to estimate im with the Clothier et al. (1992) method. All sampling dates were used to estimate with the Clothier et al. (1995) method. The sampling dates immediately after the final tracer application, 0, 2, 7, and 15 d, correspond to the numerals, 0, 2, 7, and 15 within the white circles, respectively

View larger version (20K): [in a new window]   Fig. 2 Regressions of the ln(1 - C/C0) vs. time used by the Jaynes et al. (1995) method to estimate im and at each site. The slope gives -/im and the intercept gives ln(im/) + m/(imq)

View larger version (33K): [in a new window]   Fig. 3 The predicted and measured normalized sample variance as a function of time elapsed from the start of the tracer application for each site. Here the predicted values next to the curves are derived from Eq. [10]. Note that measured values that were >1 were excluded from Site 2 on the second sampling date and from Site 4 and 5 on the last sampling date

View larger version (27K): [in a new window]   Fig. 4 The calculated relative tracer concentration in the immobile domain as a function of time. Relative immobile tracer concentrations were calculated using CXTFIT 2.0 (Toride et al., 1995), and values were obtained from the multiple tracer method

View larger version (17K): [in a new window]   Fig. 5 Soil volumetric water content as a function of time