INA — Some of the most important weed control devices in a pasture are the animals grazing it.
That’s the opinion of Chris Teutsch. The University of Kentucky forage specialist told producers at the Illinois Forage Institute, held at Rend Lake College, that proper stocking rates and rotational grazing are key elements to controlling unwanted plant growth.
“Stocking rate is extremely critical when we’re talking about weed control in pastures,” Teutsch said. “If pastures are continuously overstocked and overgrazed, and we’re not rotational stocking and not managing grazing, we’re going to have increased weed issues in that pasture.
Identifying weeds in a pasture is a bigger challenge than in a row-crop operation, since pastures contain multiple plant species. And some pasture “weeds” are beneficial. One study indicates that in their vegetative state, giant foxtail, common ragweed and redroot pigweed have some nutritional properties equal to alfalfa.
“If your goal is to eradicate weeds from pastures, you’re going to lose your mind because it’s never going to be done,” Teutsch said. “What we’re doing is managing weeds.”
Proper stocking rates vary by soil types, forage base and management practices. But in general, Teutsch recommends that cow-calf producers maintain pastures of 2 to 2.5 acres per cow.
“I encourage people to start in a little wider stocking rate — maybe 3 acres per cow/calf unit,” he said. “Increase that as your management skills increase. The best defense against weeds is having that well-managed acre of sod that’s going to exclude weeds from germinating.”
Successful producers do a good job of managing both the residual height of forages — adjusted by how closely the plants are grazed — and how long the pasture is rested between grazing.
“We don’t think of this as a weed-control program, but it is really an important part of weed control because we can impact the density of our sod by how we manage that plant under grazing” Teutsch said. “That’s what we mean when we’re talking about improved grazing management. That’s going to help us maintain a healthy and vigorous sod that’s going to exclude weeds from that pasture.”
“The problem with herbicides is, when you kill that weed in the pasture, it creates a hole. And what grows in the hole? A weed. So it’s like a revolving door,” Teutsch said. “If you have a weed control program based solely on herbicides, the chances of that being successful is pretty slim.”
Also, herbicides can rob pastures of some nutritious weed species. Teutsch would like to see farmers match a herbicide to the weed in order to get control.
Clipping can also be effective as a means of keeping forages at the height of their nutritive value. Timeliness is key, as it should be done before the plant goes to seed. Removing plants too close to the ground is a danger, as that could deplete root reserves.
Clipping also comes with a cost. It could cost anywhere from $12 to $20 an acre and $30 to $60 per cow.
“Clipping pastures is important, but it’s not free,” Teutsch said. A lot of times we wait too long. After weeds are in reproduction stage, it makes us feel good, but we’re just spreading that weed seed around the pasture. Sometimes applying a herbicide may be a better option than clipping pastures.”
credit:thesouthern.com