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 Zacharias, S. Articles by Smith, C. N. Search for Related Content PubMed Articles by Zacharias, S. Articles by Smith, C. N. Agricola Articles by Zacharias, S. Articles by Smith, C. N.

Stochastic Simulation of Field-Scale Pesticide Transport Using Opus and GLEAMS

Dep. of Biological Systems Engineering, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061;
Dep. of Crop and Soil Environmental Sciences, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061;
PBS&J, Bowie, MD 20716;
U.S. Environmental Protection Agency, Athens, GA 30605.

^* Corresponding author (heatwole{at}vt.edu).

ABSTRACT

Incorporating variability in soil and chemical properties into root zone leaching models should provide a better representation of pollutant distribution in natural field conditions. Our objective was to determine if a more mechanistic rate-based model (Opus) would predict soil water and pesticide mass in the soil profile more accurately than a capacity-based model (GLEAMS) when spatial variability and uncertainly in parameters are considered. Predictions of spatial variations of soil water content and movement of aldicarb [2-methyl-2-(methylthio)-propionaldehyde O-(methylcarbamoyl) oxime] and metolachlor [2-chloro-N-(2-methoxy-1-methylethyl) acetamide] in the root zone were compared using 3 yr of observed data from a 3.9-ha agricultural field in southwest Georgia. Spatial variability of soil physical properties, pesticide properties, and pesticide application were described using probability distributions fitted to measured field data, after removing spatial trends that were physically meaningful. There were significant differences in mean soil water content predicted by the two models, although variations around the mean were comparable. Pesticide mass predictions were different on most post-application dates in both mean and spatial variation. The less rigorous GLEAMS predicted mean depth-averaged soil water content and pesticide mass in the 1.2-m profile at least as good as the more mechanistic Opus, although it did not simulate depth distributions of water or pesticide mass as well as Opus. GLEAMS simulated spatial variations of depth-averaged soil water content and pesticide mass in the field with reasonable accuracy while employing fewer parameters that exhibit lower spatial variability.

This article has been cited by other articles:

				E. R. Bayless, P. D. Capel, J. E. Barbash, R. M. T. Webb, T. L. C. Hancock, and D. C. Lampe Simulated Fate and Transport of Metolachlor in the Unsaturated Zone, Maryland, USA J. Environ. Qual., May 1, 2008; 37(3): 1064 - 1072. [Abstract] [Full Text] [PDF]