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Article
Simulating Atrazine Transport Using Root Zone Water Quality Model for Iowa Soil Profiles
Journal of Environmental Quality
  • L. S. Azevedo, Iowa State University
  • Ramesh S. Kanwar, Iowa State University
  • P. Singh, Iowa State University
  • Lajpat R. Ahuja, United States Department of Agriculture
  • L. S. Pereira, Universidade Técnica de Lisboa
Document Type
Article
Publication Date
1-1-1997
DOI
10.2134/jeq1997.00472425002600010023x
Abstract
The pesticide component of the Root Zone Water Quality Model (RZWQM) was calibrated and evaluated for two tillage systems: no-till (NT) and moldboard plow (MB). The RZWQM is a process-based model that simulates the water and chemical transport processes in the soil-crop-atmosphere system. Observed data on atrazine concentrations in the soil profile, for model calibration and testing, were obtained from a field study in Iowa. Two statistical parameters, maximum error (ME) and coefficient of determination (CD), were used to evaluate the ability of the RZWQM to predict atrazine concentrations in the soil profile. The ME, CD, and other statistical tests indicated that there was a significant difference between predicted and observed atrazine concentrations. Comparison of simulated vs. observed atrazine concentrations with 1:1 line showed that atrazine concentrations were overpredicted, especially in the later part of the growing season. However, the model correctly predicted depth of atrazine penetration in the soil profile. Also, the range of predicted atrazine concentrations was within the same order of magnitude as observed concentrations. Although observed atrazine concentrations were usually higher in surface layers under MB than in NT treatment, the model did not show any consistent tillage effects on atrazine distribution in the soil profile. The results from this simulation study indicated that the following factors may be critical and should be considered when simulating pesticide transport in the subsurface environment: (i) macropore flow, (ii) variation in Koc and pesticide half-life with depth, and (iii) interception of pesticide by surface residue during application.
Comments

This article is from JEQ 26 (1997): 153–167, doi:10.2134/jeq1997.00472425002600010023x.

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Open
Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Citation Information
L. S. Azevedo, Ramesh S. Kanwar, P. Singh, Lajpat R. Ahuja, et al.. "Simulating Atrazine Transport Using Root Zone Water Quality Model for Iowa Soil Profiles" Journal of Environmental Quality Vol. 26 Iss. 1 (1997) p. 153 - 167
Available at: http://works.bepress.com/rskanwar/33/