Water Quality Sensitive BMPs for Atrazine
Application
1.
Soil incorporation.
Incorporation will reduce runoff losses by approximately
67 percent compared to surface application without incorporation.
Atrazine (or atrazine tank mix products) can be incorporated into the top two
inches of soil with a field cultivator, tandem disc or other implement.
Benefit: Less atrazine is present
at the soil surface, where it is most vulnerable to runoff. A good option for
producers who use tillage prior to planting.
2.
Application timing.
The potential runoff of atrazine can be decreased by
applying atrazine just prior to planting time compared to applications in
November - January. Seasonal applied atrazine is more likely to get moved down
into the soil by gentle rains of early spring than swept off the field by runoff
water during intense pre-season storms.
Benefit: Helps reduce runoff
potential on no-till or reduced-till fields where soil applications of atrazine
are used.
3.
Reduce soil-applied rates.
Formulations with low atrazine content can still provide
excellent control of pigweed and other small-seeded broadleaf weeds while
reducing the amount of atrazine applied by as much as 33 percent.
Benefit: Maintains good weed
control of small-seeded broadleaf weeds while reducing atrazine rates.
4.
Postemergence applications of atrazine.
Postemergence mixtures contain very low rates of
atrazine yet provide excellent broadleaf weed control. Using postemergence
mixtures results in 67 percent less atrazine runoff compared to
typical preemergence soil-applied atrazine applications.
Benefit: By reducing the amount
of atrazine applied to the soil, runoff potential is reduced.
5.
Combine surface applications with postemergence atrazine.
Applying reduced soil-applied rates of approximately
one-pound active ingredient of atrazine per acre at the time followed, if
necessary, by a postemergence atrazine application can reduce atrazine runoff by
25 percent compared to applying all at planting time. This two-step
program often provides the best control of velvetleaf, cocklebur and other tough
broadleaf weeds.
Benefit: Flexible option. Can
maintain excellent weed control while reducing runoff potential.
6.
Alternative herbicides or non-chemical weed control methods.
New herbicides containing no atrazine are now available.
Using these herbicides reduces atrazine runoff by 100 percent.
However, some of these herbicides do not control ALS-resistant weeds. The use of
crop rotations, cultivation and other non-chemical weed control methods may
reduce or eliminate the need for herbicides.
Benefit: Can remove atrazine from
the picture entirely if alternative herbicides provide sufficient control or if
non-chemical weed control methods alone are sufficient.
7.
Vegetative filter strips.
Vegetative filter strips that reduce water flow rate
from the field can reduce atrazine loss up to 25 percent. Removal
of atrazine from runoff water by filter strips is directly proportional to the
amount of runoff water that soaks down into the filter strip.
Benefit: Can reduce atrazine loss
without affecting weed control effectiveness or cost.
8.
Band applications.
Banding atrazine over the row at planting or during
cultivation reduces the total amount applied on a field by 50 to 67
percent. As a result, less atrazine is available for possible runoff than
when the herbicide is broadcast over the entire field.
Benefit: Cultivation between the
rows is a good way to reduce atrazine use and still get good control.
9.
Buffer zones.
Avoid atrazine applications near water supplies and
environmentally sensitive areas.
Benefit: Can reduce atrazine loss
without affecting weed control effectiveness or cost.
December 15, 1999
Dennis Hoffman, Project Leader
Steve Dagitz, Webmaster