Estimates of herbicide use for the 20 most-used herbicides in the conterminous United States

This coverage contains estimates of herbicide use for the 20 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).

Herbicides
Herbicide use
Counties
United States

本数据集覆盖图层包含依据Gianessi与Puffer（1991）的研究成果所估算的美国本土（conterminous United States）20种最常用除草剂的使用量数据。本图层中的除草剂使用量估算值以县多边形为统计单元，分别报告了施药面积、有效成分使用量（单位：磅）以及每平方英里的使用量（单位：磅）。

Gianessi和Puffer（1991）提供的除草剂使用量估算值，列出了每个已开展使用量估算的县内，对应单一作物的施药面积与有效成分施用量。其中种植面积数据源自1987年美国农业普查，但出于保密与普查披露规则的限制，部分县级的施药面积估算值会被隐去。本数据集覆盖图层中的除草剂使用量估算值，为对应县内所有施药作物的总使用量。

本图层中代表美国本土县界的多边形，以及湖泊、河口与其他非陆地区域要素，均源自1970年版《美国国家地图集》中1:200万比例尺地图对应的数字线划图（Digital Line Graph，DLG）文件。

除草剂 除草剂使用量 县 美国