Agronomy Advice

More effective weed control on grassland

By: Philip Cosgrave

When getting the sprayer out to control grassland weeds, there is an opportunity to add a foliar fertiliser to improve weed control and ensure the long term success of the sward.

More effective weed control on grassland
More effective weed control on grassland

The effectiveness of herbicides on grassland can be improved if a foliar fertiliser is tank-mixed with the herbicide. The foliar fertiliser works by stimulating the weeds to grow more actively, which results in more of the active ingredient being taken up by the weeds.

Weed infestation of paddocks and pastures often causes a dramatic drop in both yield and quality with even a moderate infestation could result in losses of over 1 tonne dry matter per ha. Docks, nettles and thistles are most damaging, especially in established swards although other weeds such as chickweed or buttercup can often be a problem in newer swards.

The ideal time to apply herbicides is when the weeds are actively growing and in the case of docks and thistles should be during the rosette stage before the flower stem has extended. Silage crops should be sprayed around 2 weeks before cutting to allow time for systemic herbicides to be translocated into the roots to achieve full control.

Spraying reseeds with herbicide can knock the young grass plant back, especially in late autumn when growing conditions are not ideal. The use of a foliar fertiliser with the herbicide helps the grass plant cope better with the stress of being sprayed. Grass which is supplied with a full complement of nutrients at the onset of environmental stress is more resilient. The improved growth of grass seedlings will help fill in bare patches, reducing light and space for any new germinating weeds.

Applying a foliar fertiliser with the herbicide can significantly improve the recovery of the sward. Giving the grass close to the weeds a boost will help the grass out-compete the weeds and quickly recover any bare patches to avoid these being recolonised by newly germinating weed seedlings.

YaraVita Croplift Pro is ideal for this application; containing a readily available source of nitrate-nitrogen to give the grass a boost together with phosphate, potash and a full range of micronutrients. Yara recommends YaraVita Croplift Pro at a rate of 2.5 kg/ha or 1 kg/acre in conjunction with your grass herbicide. It contains a full complement of nutrients to ensure the long-term success of your new ley

YaraVita Croplift Pro can be tank-mixed with almost all common grassland herbicides, if in doubt ask your supplier about compatibility. 

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Latest advice background
Grow the future | Grassland Sulphur Grow the future | Grassland Sulphur

Spreading nitrogen and sulphur at the same time means more grass

Applying fertilisers containing nitrogen and sulphur means the grass uses nitrogen more effectively, you get more kgs of dry matter per kg of nitrogen that you apply

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