Pasture weed control for higher forage yield
Pasture weeds are outright thieves. They rob forage plants of nutrients, moisture, sunlight and growing space. Grazing lands occupy nearly 600 million acres or 40 percent of the land area of the United States, and weed and brush invasions on these acres steal some $2 billion each year.
But controlling pasture weeds is not always easy. Nor cheap. With current fuel prices, mowing can be a costly option. Also, with some weeds, especially deep-rooted perennials, mowing is only a temporary fix.
Herbicides aren’t cheap, either. But with relatively new chemicals—Chaparral, GrazonNext, Remedy, Crossbow—you can tailor a chemical recipe to the weeds you need to control. And the first step is to identify the weed (or weeds) and what you need to use to control it.
For pastures with several different weeds, a broad-spectrum herbicide with residual activity will be the most effective, and most cost-effective. If brush or other woody plants are in the stand, use a product labeled for both weed and brush control, or tank-mix to get the right control spectrum. If sprouts (especially red cedar) are waist high or taller, you may need to team up your sprayer with a chainsaw.
Some producers with legumes in the stand are reluctant to spray pastures. And spraying does take out clover along with the weeds. But grazing lost to weed pressure may outweigh the benefits of a legume. Kevin
Bradley believes this is the case.
Bradley, a University of Missouri weed scientist, split continuously-grazed pastures in two, controlling the weeds in half of the pasture and leaving the other side with weeds and whatever legumes were in the stand.
After the weed treatment, to monitor where cows grazed, Bradley fitted some of the cows in the herd with GPS collars. Averaged over a grazing season, cows spent 74 percent of their grazing time on the treated side of the pasture, versus 26 percent of the time on weedy grass with clover.
“Solve weed problems first and then bring back the clover,” Bradley concluded. “Once weeds are gone, as long as you keep good health and vigor of the stand, you can go years without having weeds germinate again.”
Timing is critical when it comes to controlling most weeds. All annual weeds are most susceptible to spraying when they are small and actively growing, before flowering and seed production begins. Fall can be a good time to control biennial and perennial weeds, such as thistles. Fall rains and cooler temperatures bring on a flush of germination and regrowth of biennial weeds. These lush weeds and new seedlings are susceptible to herbicides. And if you use a product with residual activity, you’ll continue to get control through early spring.
Spray the right amount at the right time. For broadcast sprays, apply the herbicide (or herbicides) in 10 to 20 gallons of total spray mix per acre. For brush control, spray at least 20 gallons to give the sprouts a good soaking. With both weed and brush killers, use a recommended rate of an ag surfactant to help the spray stick to the plants.
For chemical control recommendations, contact your MFA Agri Services outlet for the latest in approved herbicides and application rates.