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Considering Weed Control in Agricultural Grassland

weeds in agricultural grassland

Weed Control in Agricultural Grassland

Graham Ragg, Senior Agronomist and Product Manager, Mole Valley Forage Services discusses weed control in agricultural grassland


Weed control in grassland is important for grazing and silage quality and yield. With the emphasis on producing the lowest cost feed on farm to feed livestock, attention to solving weed problems in grassland is vital. The main culprits are docks, thistles and nettles, but buttercups, dandelions, daisies and plantains can also form an unwanted part of the sward. A 10 to 20% infestation of a combination of these weeds is not uncommon. This will result in a similar reduction in grass yield and quality. This, in practice might mean a potentially productive ley is no more than ‘fill belly’, which only serves to maintain the stock, rather than form part of the ‘productive ration’ so having a weed free ley will make a significant difference to farm profitability.

Walking and assessing weed problems in your grass in March is a good time to plan a weed control programme for the year. Weeds need to be controlled before they use up valuable nutrients and water reserves, before they flower and seed and before the pasture is grazed or cut for silage.

The actual timing of spray applications will depend on the year and location of the grassland, but in the case of docks ( usually the biggest problem ) early-mid April when the leaves cover roughly the same size as a ‘dinner plate’ is the best time for control. The choice of a ‘grass safe herbicide’ is vital, as every blade of grass is precious. Avoid using herbicides with a reputation for being harsh on the grass.

Modern translocated herbicides, containing active ingredients such as triclopyr (found in Doxstar Pro and Pastor) are the most reliable solution for controlling broad leaved weeds in grassland. Crucially, they are very safe to grass and will not adversely affect its subsequent growth, ensuring maximum productivity.

If the opportunity to spray in April is missed, then spraying between cuts of silage may be a solution. Normally wait 21 days after a cut to allow the docks to regrow to rosette stage (approx. 25cm across, the perfect size for spraying and leave about 3 weeks before cutting again. This gives time for the active ingredients to produce a long lasting effect. While this means that first cut yields and quality will be affected by any weeds present, at least subsequent cuts will produce more and better silage, so will help lower feed costs.

Call your local Farm Sales Office for advice on weed control.

Source Details

Graham Ragg, Senior Agronomist

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