Dr. Brent Sellers, associate professor of agronomy and Extension weed-science specialist at the University of Florida The details differ from region to region and even pasture to pasture, but the first step for producers is to scout their pastures this fall. Take stock of which forage species and which weeds are present and their relative populations. Check pastures regularly to monitor changes in plant populations, or in rangeland environments, ask ranch hands to monitor forage conditions while they check cattle. Also look for bare or thinning patches in the pasture, which can become next season’s weed patch.
An increase in pasture weeds can indicate overgrazing, but some weed species also can suggest a need for fertility management, adjustments in soil pH or disease problems in desirable forage species. In problem areas, take soil samples and use the analysis to plan fall or spring fertilizer or lime applications.
Also keep an inventory of weed species to track which species are present and their prevalence. Consult with your county Extension agent, state Extension specialist or other crop-protection expert to determine the best products and timing of treatment for pasture weeds, and plan stocking rates accordingly based on forage production.
Finally, especially with the drought conditions in many areas this year, producers need to watch for toxic weeds in pastures. In severely drought-stressed pastures, weeds often are the only green plants available at this time of year. If some of those weeds are poisonous, the scarcity of desirable forage increases the likelihood of cattle consuming toxic doses. Nitrate levels also can become elevated in weeds growing in dry pastures, so check for potentially toxic plants before turning cattle out to weedy pastures, and consult with a weed specialist if necessary.