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Herbicides in the Pecatonica, Trempealeau, and Yahara Rivers in Wisconsin, May 1997-July 1998

Fact Sheet 167-99
By: , , and 
https://doi.org/10.3133/fs16799

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Abstract

In 1997, Wisconsin farmers applied 8.7 million pounds of herbicides on corn. The five most commonly applied herbicides (in lb (pounds) of active ingredient per acre) on corn in 1997 were atrazine, metolachlor, acetochlor, alachlor and cyanazine. A 1996 study by the U.S. Geological Survey (USGS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) found that the most heavily applied agricultural herbicides were detected more frequently and at higher concentrations in the Pecatonica and Yahara Rivers in southern Wisconsin than the less heavily applied herbicides (Graczyk and Vanden Brook, 1997). The calculated herbicide loads a from May 15 to July 15, 1996 at the Pecatonica River ranged from 47.2 lb of alachlor to 484 lb of atrazine. For the Yahara River, loads ranged from 36.1 lb of alachlor to 289 lb of atrazine. The yields b (load per square mile) for atrazine were similar in the two water- sheds. This result was unexpected because the use of atrazine is prohibited on 94 percent of the Yahara River Watershed, but on only 4 percent of the Pecatonica River watershed. The unexpected atrazine result led to a continuation of the study in 1997 and 1998, when samples were collected again at the two sites sampled in 1996, and at a site in the upper third of the Yahara River Watershed that is entirely under atrazine use prohibition. For comparison purposes, a site in west-central Wisconsin also was sampled to determine herbicide loads and yields in another geographic area in the state

Suggested Citation

Graczyk, D., Vanden Brook, J.P., Rheineck, B.D., 1999, Herbicides in the Pecatonica, Trempealeau, and Yahara Rivers in Wisconsin, May 1997-July 1998: U.S. Geological Survey Fact Sheet 167-99, 6 p., https://doi.org/10.3133/fs16799.

ISSN: 2327-6932 (online)

ISSN: 2327-6916 (print)

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Herbicides in the Pecatonica, Trempealeau, and Yahara Rivers in Wisconsin, May 1997-July 1998
Series title Fact Sheet
Series number 167-99
DOI 10.3133/fs16799
Year Published 1999
Language English
Publisher U.S. Geological Survey
Contributing office(s) Wisconsin Water Science Center
Description 6 p.
Country United States
State Wisconsin
Other Geospatial Dodge, Fulton, Martintown, Pecatonica River, Trempealeau River, Windsor, Yahara River
Online Only (Y/N) N
Additional Online Files (Y/N) N
Additional publication details