Proper Range Management: Monitor the range for weeds, poisonous plants
Producers should plan to examine their range this spring, monitoring it for both weeds and poisonous plants. “The best offense is a good defense,” according to Jerry Volesky, range and forage specialist for the University of Nebraska. “The best defense against weeds is grazing management that maintains or increases range condition or ecological status,” he said.
Some of the more common poisonous plants and weeds producers should be on the lookout for include Riddell groundsel, which is becoming relatively common in the Sandhills of Nebraska; Poison hemlock, which grows in wet areas near streams and riverbanks; Prairie larkspur and Lambert crazyweed, which are commonly found on prairies; and Nightshade.
Some poisonous plants have naturally occurring toxic plant compounds that make them poisonous to animals, and sometimes humans, Volesky said. These compounds can be alkaloids, hydrocyanic acid, cicutoxin, locoine, glycosides and resinoids, and nitrates. Nitrates can occur in warm-season annual forages, small grain forages and in several plants or weeds. Nitrates can develop as a result of drought, hail and herbicides, or as a result of excess nitrogen from fertilizer or manure, Volesky said.
Animals who consume poisonous plants typically need to consume a quantity of it before it will cause health concerns. “One bite usually doesn’t cause health issues,” he explained. “The key is for producers to know what species of plants they have in their area, and be able to identify them,” he explained. If plenty of desirable plants are available, animals typically shy away from the poisonous ones. “Different animals have different grazing habits. If the animal is moved to a new pasture it hasn’t been to before, and isn’t familiar with the forage, it may test a new plant,” he said. Animals may also consume poisonous plants if there is limited forage available, like during a drought or overgrazing situation, he added.
Volesky offered the following suggestions to reduce poisonous plant intake:
• Know and identify potential toxic species in your area.
• Avoid placing livestock in areas where poisonous plants are common.
• Use control measures if excessive numbers of poisonous plants are establishing.
• Time grazing to provide high levels of desirable forage and reduced toxin periods of poisonous plants.
“A weed is a plant that is not valued where it is growing,” Volesky said. “Weeds are often vigorous, and they tend to out-compete our desirable plants,” he added.
If producers fail to manage weeds on the range, the undesirable plants can buildup to the point that they reduce the amount of productive plants on the range. “It is important to maintain healthy and productive pastures, and the grasses in those pastures,” Volesky said.
Some of the common native range and pasture weeds Volesky discussed were Horseweed (Marestail), Broom snakeweed, Verbena, Western ragweed, Western Ironweed, Yucca, Annual sunflower, Cudweed sagewort, Eastern red cedar, Sandbur, Buck brush, and Foxtail barley. Some of the exotic range and pasture weeds include Downy brome, Smooth bromegrass, Kentucky bluegrass, Curly dock, Field bindweed, Kochia, and Common lambsquarters. “Some people may not consider Smooth bromegrass and Kentucky bluegrass as a weed, but for producers who are doing pasture restoration and only want native plants species present, Smooth bromegrass and Kentucky bluegrass, which are both introduced exotics, can cause some problems,” he said.
Some range and pasture weeds like Musk thistle, Canada thistle, Leafy spurge, and Phragmites are considered exotic, invasive and noxious, Volesky said. “These plants need to be controlled to keep them from spreading,” he said.
“Can grazing management alone reduce or stop the invasion of undesirable, weedy species?” Volesky asked. Depending upon the species, the answer could be yes or no, he answered. “In some cases, no matter how good of a job we do managing our pastures, there are some species that will still come in there,” he explained. Species like Musk thistle, Canada thistle, Leafy spurge, Eastern red cedar, Downy brome, Diffuse knapweed, Russian olive, and Chinese elm can continue to increase, even on well managed range or range in a high ecological state, he said.
Producers may want to consider applying specific herbicides to specific weeds to get the best control, Volesky continued. “There are many really good herbicides on the market that will do a great job managing weeds,” he said. “However, keep in mind that if you are targeting one specific weed or species out there, what other plants may be affected by what you spray,” he cautioned.
Some chemicals also are more effective on certain weeds than others, Volesky continued. “I would encourage everyone to do a little homework when selecting which chemical would be the most effective,” he said. “Of course, the timing of the application and the growth stage of the plant are critical to getting the best results,” he stated.
Volesky encouraged producers to refer to the “2012 Guide for Weed Management”, which is available through the University of Nebraska Extension. It has sections designated for range and pasture, and troublesome weeds, he said. For more information on weed control and poisonous plants, Volesky can be reached at 308-696-6710, or at: firstname.lastname@example.org.
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