Estimates of herbicide use for the forty-first through the sixtieth most-used herbicides in the conterminous United States

The herbicide-use estimates in this coverage are intended for use as a means
for estimating regional herbicide use, and for producing maps showing relative
rates of herbicide use across broad regions of the United States.

This coverage contains estimates of herbicide use for the forty-first through
the sixtieth most-used herbicides in the conterminous United States as reported
in Gianessi and Puffer (1991). Herbicide-use estimates in this coverage are
reported for each county polygon as acres treated, pounds of active ingredient
used, and pounds used per square mile.

The herbicide-use estimates provided by Gianessi and Puffer (1991) list acres
treated and pounds of active ingredient applied for a given crop in each county
for which use has been estimated. Cropping data are from the 1987 Census of
Agriculture, and are subject to occasional suppressions of acreage estimates at
the county level due to problems of confidentiality and census disclosure
rules. The herbicide-use estimates included in this coverage are totals of use
on all crops treated in a given county.

The polygons representing county boundaries in the conterminous United States,
as well as lakes, estuaries, and other nonland-area features were derived from
the Digital Line Graph (DLG) files representing the 1:2,000,000-scale map in
the National Atlas of the United States (1970).

[Summary provided by USGS]