Grassland weeds need to be controlled to ensure the long term productivity of grasslands. Weeds compete with grass for space, light, nutrients and water, limiting the yield in the field. Weeds also have a lower feed value and reduce livestock performance, some weeds are toxic to livestock and can cause health problems and even death.
Controlling weeds before they seed is important to prevent the plants from spreading further, a single dock plant can produce up to 60,000 seeds per year and these seeds can be viable for up to 80 years. Chickweed can produce over 2,500 seeds per plant and begin to shed seed from May, the plant has a very low dry matter and can cause issues with silage quality.
Timing of herbicide application is key to getting the best results. Applications made too early or too late will not be as effective. Generally weeds are now at the ideal stage for control as they are actively growing. Docks should be targeted when they are vegetative and about the size of a dinner plate, chickweed is best controlled pre flowering. It is important to check the herbicide for the exclusion period after treatment and build this into your plan before treating a field. If some fields need to be grazed within 7 days it is better to wait until the paddock has been grazed and treat afterwards, if the weeds have become too strong it may be best to top and treat the regrowth.
To select the most effective herbicide assess your fields and identify which species are present, the most common weeds in grassland are docks, chickweed, nettles, ragwort and thistles. Each herbicide will have a different impact on these weeds, meaning you may need to use different products in different fields. It is also important to check if there is clover present in the paddock as you may wish to use a clover safe spray to protect the plant.
To find the best method to control weeds on your farm speak to your local Fane Valley Agronomy and Forage Specialist, call in to your local Fane Valley store or call 028 9261 0485