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Article
Structural Equation Modeling of Dynamics of Nitrate Contamination in Groundwater
Journal of the American Water Resources Association
  • Zhi-Jun Liu
  • George R. Hallberg
  • George P. Malanson, University of Iowa
Document Type
Article
Peer Reviewed
1
Publication Date
1-1-1997
DOI of Published Version
10.1111/j.1752-1688.1997.tb03548.x
Abstract

Most research on the temporal aspect of nitrate pollution in water resources has focused on surface water. Comprehensive studies on the dynamics of nitrate in ground water are lacking, especially on a drainage basin scale and for relatively long periods of time. In this study, structural equation modeling is applied in investigating the influences of climate, hydrology, and nitrogen management in agricultural production on nitrate concentration in the Big Spring Basin, Iowa, over a 10-year period. The study shows that for given hydrogeological settings, nitrogen management practices and climate are the two most important factors that affect nitrate dynamics. The long-term trend of nitrate is closely related to the nitrogen input primarily determined by management practices. The potential effects of nitrogen management, however, are contingent on the variations of climate. The improvements in water quality (reduced nitrate concentration and loads) in relation to improved nitrogen management are often overshadowed by the impact of climate, especially in extremely dry or wet years. The variations of climate and hydrology have much greater impacts on the nitrate dynamics than the changes in nitrogen input. This study reveals significant seasonal variation in the relations between nitrate concentration and influencing factors, which is also closely related to the seasonal variation in climate. Assessment of management practices and resultant water quality should consider the impact of short- and long-term climate dynamics.

Keywords
  • structural equation modeling; nitrate dynamics; sustainability
Journal Article Version
Version of Record
Published Article/Book Citation
Journal of the American Water Resources Association, 33 (1997), pp. 1219-1235. doi:10.1111/j.1752-1688.1997.tb03548.x
Rights
Copyright © The American Water Resources Association, 1997. Posted by permission of the publisher.
Disciplines
Citation Information
Zhi-Jun Liu, George R. Hallberg and George P. Malanson. "Structural Equation Modeling of Dynamics of Nitrate Contamination in Groundwater" Journal of the American Water Resources Association Vol. 33 Iss. 6 (1997) p. 1219 - 1235 ISSN: 1093-474X
Available at: http://works.bepress.com/george_malanson/88/