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Originally published Vol.
1, Issue 1 (February 2003)—updated July 2006
ARMS Data Highlights Trends in Cropping Practices
C.S.
Kim, William Quinby, Tim
Payne
Since 1996, U.S. farmers have responded
to a number of industry-altering changes, including
lower crop prices, the availability of genetically
engineered seed, and environmental incentives embodied
in farm legislation. How have these changes affected
production and conservation practices used by farmers?
USDA’s Agricultural Resource Management Survey
(ARMS) provides a source of information about practices
on sample fields in major field-crop-producing states.
Data from 1996 to 2002 show significant trends beginning
to emerge, which may have implications for environmental
quality.
Genetically Engineered
Soybeans
HT seed and glyphosate
herbicide use soared...
Use of herbicide-tolerant (HT)
soybean seed has enabled farmers to use glyphosate
herbicides that are effective in controlling weeds
during crop growth.
…while overall herbicide use
decreased on soybeans...
With soybean producers relying
more on glyphosate herbicides, the number of herbicide
treatments has declined. The annual per-acre average
of all herbicide active ingredients also declined.
Adopting HT soybean varieties has allowed producers
to switch to herbicides that are more effective
at lower rates of use per acre.
…and cultivation for soybean
weed control dropped.
The use of glyphosate herbicides
during soybean growth allowed farmers to reduce
cultivation for weed control, especially on conventionally
tilled soybeans (i.e., soybeans planted on land
plowed or tilled so as to leave little or no crop
residue, one-fifth of planted acreage in 2002).
Tillage
Conventional tillage trend reversed
on highly erodible land
The recent decline in conventional
tillage on highly erodible land reverses a previous
trend toward greater potential for soil erosion.
Soil-conserving tillage is compatible with HT seed
and improved herbicides for effective weed control.
Crop Rotation
More corn/soybean rotation
in the Northern Plains and Lake States
Rotating corn with soybeans increased
in regions where continuous corn production had
been the norm. Adding soybeans to the rotation may
reduce use of nitrogen fertilizers and insecticides.
Nutrient Management
Nitrogen fertilizer application rates
on corn in rotation after soybeans are lower
When nitrogen is applied on corn
in rotation following soybeans, the application
rates are lower due to the “carryover effect”
from the increased soil nitrogen provided by the
soybean crop during the previous growing season.
This trend lowers the amount of nitrogen fertilizer
required for the corn crop and reduces the risk
of nitrogen runoff to surface waters.
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