Weed control is not often top of livestock farmers' agendas, but a planned weed programme can improve grass DM/ha by more than 10%.

That is the figure from crop protection company Nuform, who claim that a weed control programme would deliver a return on investment of up to 14:1. Timing of the actual herbicide along with the choice of product used is however critical, to maintain clover rich swards.

“Dairy, beef and sheep farmers already believe they can get more from their grass – the cheapest form of feed, however they are not sure how to,” said Nufarm’s Simon Bishop.

“The yield benefits of weed management are not yet widely understood by growers, but we know having clover safe options are important. Controlling common weeds such as Docks and Thistles from a 10% infestation level will deliver an extra 10% of grass dry matter,” he told a media briefing recently.

Results from a recent independent survey reveal that livestock farmers concentrate more on fertiliser and seed to improve grass growth and quality instead of weed control, with only half of all grassland farmers having done some form of weed control in the last year.

As a result, little more than 5% of UK grassland has a herbicide application in any given year, and few grassland farmers treat more than 10% of their pasture in any season.

It was for this reason that the company launched a new comprehensive programme in Grassmanship to help farmers manage their grassland better and benefit from increased production and yield.

Independent grassland consultant, Dr George Fisher said: “Weed control is a key element of productive grassland farming and it is important that herbicide applications are effective, made safely and with care for the environment.

“Every 1% increase in weed ground cover will result in a 1% decrease in grass growth, thereby controlling common weeds in a grazing sward with 10% infestation levels could improve yield from 10t DM/ha to 11t DM/ha enabling improved grazing availability and subsequent stocking rates to deliver a 14:1 return on investment (ROI). Similar results can be achieved from grassland for silage,” he said.

“Achieving that level of ROI is linked to correct timing of herbicide application. Timing is everything – herbicides applied too early or too late will not work as effectively, if at all.

“Generally, herbicides should be applied when weeds are healthy and the leaves actively growing. Once stem extension starts, leaf growth is insufficient for the herbicide to work effectively.

“Weeds in reseeds are best controlled when the grass is at the two to three leaf stage. Docks and Chickweed are the two most critical weeds to control in reseeds and must be controlled at the seedling stage. Herbicide application is essential before the first grazing. Clover safe options are available such as CloverMaster and Squire Ultra, but again, timing of application is crucial.

“In established and permanent grassland, it is important that farmers assess weed pressure as soon as grass starts to grow in spring. Early assessment allows time to prepare, choose the right product and plan for timely application, either using on-farm resources or getting in a contractor to do the job.”

Dr Fisher added: “This spring provides the opportunity for all livestock farmers to make more from their forage by adopting a serious approach to weed control. Timeliness and the right product are critical to successful weed control, particularly if a sward has 10% weed ground cover or more. That is why early assessment and planning are so important towards achieving a significant return on investment.”

With average weed control costs of £37 per ha based on produce costs of £20-£25/ha and contractor costs of £13.69/ha, trial results revealed an grazing-based dairy farmer would see his stocking rate: improving yield by 10%, from 10t DM/ha to 11t DM/ha. This additional 1t DM @12ME contains 12,000MJ ME, which when 5.4MJ ME is required to produce one litre of milk

results in additional milk production of 1778 litres/ha @ 28ppl = £498. This points to a ROI 14:1.

Similarly, a grazing-based dairy farmer replacing concentrate feed: improving yield by 10%, from 10t DM/ha to 11t DM/ha, would see an additional 1t DM @12ME contains 12,000MJ ME, which compared to a 13% ME concentrate could be used to replace 0.83t concentrate @ £210t, which is the equivalent of £174 and a ROI 5:1.