story to find out more.
Dale Shaner examines a patch of field bindweed in a cornfield. Mapping these
weed patches and applying herbicides only to the patches will reduce herbicide
use and cost. Click the image for more information about it.
Soil Is Key to Effective Weed Management
McGinnis August 16, 2006
The fight against weeds is getting dirty.
At Fort Collins, Colo., scientists with the Agricultural Research
Service (ARS) are turning to soil to
promote weed control.
Soil variability, an important factor in treating weed-infested
fields, can be gauged by measuring different soils' electrical conductivity
(EC). A soil's EC assesses how easily it allows a current to pass through it.
Soils with a higher EC generally have more clay and organic matter and require
Farmers can use EC to create herbicide application maps, allowing them
to adjust application rates based on variations within the soil. This, in turn,
reduces the risk of excessive herbicide leaching while maintaining
Herbicide selection is an equally important aspect of weed control.
L. Shaner, a plant physiologist in the
Management Research Unit at Fort Collins, has shown that atrazine, a widely
used herbicide, sometimes breaks down rapidly in fields where it has been used
for many years. This could be the result of bacteria which reduce the herbicide
to its elemental parts.
Herbicide degradation makes weed control difficult, so farmers have to
spend more time and money to apply additional herbicide. An inexpensive field
kit could help farmers and crop consultants identify whether fields are at risk
before they apply atrazine.
Shaner and his colleagues are investigating whether test strips used
to analyze water for atrazine's presence could be modified to test the soil.
Though a field kit is still in the early stages of development, Shaner believes
it could help reduce herbicide overdose.
about this research in the August 2006 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.