Around this time of year, I always see a large number of pastures being
mowed for weed control, not hay production. Have you ever stopped to
think about what it costs to mow a pasture? Mowing is costly, and pastures
that have weed problems this late in the growing season have no chance
for optimum weed control.
The following table shows the cost of mowing versus applying herbicides.
All herbicide treatments except Grazon P+D are more economic than mowing.
However, Grazon P+D is the only herbicide listed that offers significant
residual weed control, which is worth the additional cost when weed infestations
are severe.
Cost of mowing versus spraying pasture for
weed control |
Method |
Rate/Acre
(Pint) |
Application
($/Acre) |
Cost of Herbicide
($/Acre)
a |
$/Acre |
Mowing |
- |
- |
- |
10.00
b
|
2,4-D Amine |
2 |
3.00 |
3.30 |
6.30 |
Banvel + 2,4-D |
2 |
3.00 |
6.50 |
9.50 |
Grazon P+D |
2 |
3.00 |
7.50 |
10.50 |
a Cost of herbicide includes surfactant at 1 quart per 100 gallons of water.
b Doane's Agricultural Report newsletter, vol. 62, no. 21-6, 1999. |
The majority of pasture weeds are annual broadleaf species that can
easily be controlled in the spring with a single herbicide application.
A timely application of 2,4-D amine or a Banvel and 2,4-D tank mix controls
annual weeds before they have time to reproduce or, more important, compete
with your warm-season forage. Eliminating weed competition for nutrients
and moisture in the spring is critical, since over 60 percent of the
summer's forage is produced from May through June. Mowing does not stop
weed competition through the spring and will not stop weeds from producing
seed. Even after being mowed, the cut plant can finish its life cycle
and produce viable seed. Mowing in the summer is for aesthetics only.
It does nothing to enhance forage production. Weed competition has already
done its damage, and by late June a majority of pasture weeds are mature.
Mowing tops the valuable forage, taking the most nutritious portion of
the plant.
I do not recommend an annual herbicide application. Herbicides should
be applied to get a handle on a weed problem in the spring. Typically,
with good soil fertility and grazing management programs, weed populations
decrease over time. Providing sufficient levels of fertility while maintaining
a forage stubble height of at least 3 inches in introduced pastures produces
grass. Applying herbicides controls weeds; it does not produce grass.
Concentrating inputs on forage production and grazing management instead
of weed control will produce a greater return for your investment.
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