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Preferential flow estimates to an agricultural tile drain with implications for glyphosate transport

Journal of Environmental Quality

By:
and
DOI: 10.2134/jeq2006.0068

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Abstract

Agricultural subsurface drains, commonly referred to as tile drains, are potentially significant pathways for the movement of fertilizers and pesticides to streams and ditches in much of the Midwest. Preferential flow in the unsaturated zone provides a route for water and solutes to bypass the soil matrix and reach tile drains faster than predicted by traditional displacement theory. This paper uses chloride concentrations to estimate preferential flow contributions to a tile drain during two storms in May 2004. Chloride, a conservative anion, was selected as the tracer because of differences in chloride concentrations between the two sources of water to the tile drain, preferential and matrix flow. A strong correlation between specific conductance and chloride concentration provided a mechanism to estimate chloride concentrations in the tile drain throughout the storm hydrographs. A simple mixing analysis was used to identify the preferential flow component of the storm hydrograph. During two storms, preferential flow contributed 11 and 51% of total storm tile drain flow; the peak contributions, 40 and 81%, coincided with the peak tile drain flow. Positive relations between glyphosate [N-(phosphonomethyl)glycine] concentrations and preferential flow for the two storms suggest that preferential flow is an important transport pathway to the tile drain. ?? ASA, CSSA, SSSA.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Preferential flow estimates to an agricultural tile drain with implications for glyphosate transport
Series title:
Journal of Environmental Quality
DOI:
10.2134/jeq2006.0068
Volume
35
Issue:
5
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Environmental Quality
First page:
1825
Last page:
1835