By Samantha Daniel
August always seems to be a time when certain weeds become quite noticeable in pastures. That is especially true of areas that have had abundant summer rains and in pastures that have relatively thin grass stands, where animals congregate, or if some overgrazing has occurred.
Common pasture weeds include annuals such as sunflowers, lamb’s quarter or kochia and perennials like western ragweed, ironweed and verbena.
Spraying weeds now does little good as many weeds are too large to kill. In species that produce seed, herbicides might only reduce some seed production. If the goal is to improve appearance, shredding areas that have an abundance of weeds might be the best option, and may reduce some seed production, if it’s not already too late.
Two other approaches are better for long-term weed control. First, focus on the grazing management of your pastures with an overall goal to increase the health, vigor and density of your grass. Use the proper stocking rate and develop a good rotational grazing plan. Healthy, competitive grass stands are essential to reduce weed populations economically over time.
Second, target herbicide applications for when they will do the most good. Both perennial and annual species can be better targeted with a spring application when plants are smaller and therefore easier to control. For perennials, if a second application is needed, waiting closer to a killing frost is best. These fall applications can be more effective as more product is translocated down to the roots.
Pasture weeds may look unsightly now but hold off on spraying. Improve grazing management and time herbicides for the best window of control so herbicides won’t be needed as often in the future.
Source : unl.edu