Pasture weed management considerations


Temperatures are on the rise as spring is just around the corner here in Clinton County. Livestock producers may already be walking their pastures determining what this year’s grazing conditions could look like. Scouting in late winter or early spring is a good idea to identify thin or bare spots within your pastures and gives you some time to plan before the grazing season. Thin or bare spots in your pasture are a great location for weeds to grow, so it is important to make considerations about how you plan to manage weeds in your pasture this spring.

The best way to approach weed control in most situations is through an Integrated Pest Management system (IPM), as herbicides are an effective tool, but they are only one tool in our weed management toolbox. Cultural control is the strongest measure we can take against weeds in our pastures and hayfields. Maintaining a healthy forage stand is imperative in reducing weed infestations, as healthy forages can typically outcompete many weed species.

So, what makes up a healthy pasture?

· Make sure you have the correct pH

· Sufficient Phosphorus & Potassium levels

· Not overgrazing pastures

· Use sacrifice lots during the winter

· Pulling animals off wet pastures after a rain

· Pasture rotation

Many weed species enjoy growing in soils with low pH or low fertility, Broom Sedge as an example is an indicator of low pH soils. You could absolutely spray Broom Sedge with a herbicide, although that would be a Band-Aid solution, whereas managing pH levels would be a long-term solution. This is also true of the Buttercup weed which is often prevalent in overgrazed pastures with compacted ground. Cultural management would be a long-term solution in control of this weed. This is why it is important to identify weeds and understand their biology.

It is important to note that even if the pasture is managed well culturally, there is no solution for pastures that are overgrazed and overstocked. Make sure to have the appropriate animal units on your pasture throughout the grazing season.

Here are a few tips for mechanical/cultural control of weeds based off their biology:

· Annual weeds- mow just before or soon after flowering to prevent seed spread.

· Biennial weeds- mow in the second year of life stage to reduce strength and prevent vegetative growth and seed set, best to mow after bolting to deplete energy (be thinking Poison Hemlock).

· Perennial weeds- mow in early bud stage when root energy is at it’s lowest, mowing in addition to chemical control works best (be thinking Horse Nettle).

In using herbicides to control weeds, make sure you read the entire label. The label is the law, and you are liable if you do not follow the label. Make sure to pay close attention to restrictions like environmental hazards to water, bees, or re-seeding other crops. Many herbicides also have restrictions on when hay can be mowed or grass can be grazed after chemical application, withholding dates for slaughter, lactating animals, or spreading manure to name a few.

Tips for herbicide application timing:

Annual weeds- Best controlled during seedling and early vegetative stages, as plants get closer to the reproduction stage, they get harder to control.

Biennial weeds- Best controlled as seedlings or in rosette state with most broadleaf herbicides, can be very hard to control during bolting stage.

Perennial weeds- Best controlled in early-bud stage (2 weeks before flowering). Cool season perennials like Canada thistle and curly dock can be controlled well in mid-to late fall.

If you have any questions about weed control in your pastures, gardens, or crop fields please give me a call at the Clinton County Extension office: 937-382-0901 or email me at [email protected]

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