Successful weed control can deliver clear benefits in grassland yield, according to Simon Bishop, business manager at Nufarm.
However, weed control is often not at the top of grassland farmers’ agenda. He says: “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. The yield benefits of weed management are not yet widely understood by growers, but we know that having clover safe options is important. Controlling common weeds such as docks and thistles from a 10% infestation level will deliver an extra 10% of grass dry matter.”
An independent survey recently commissioned by Nufarm highlighted the fact weed control is not at the top of livestock farmers’ minds as being essential to producing good quality grass cover, compared to fertiliser and seed.
Mr Bishop says: “While only half of all grassland farmers had done some form of weed control in the last year, 80% of those had a general feeling it was about ‘tidying up weeds’; just 20% considered crop protection as improving grass production.
“Consequently, 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. This is why we have launched a new comprehensive programme in ‘Grassmanship’ to help farmers manage their grassland better and benefit from increased production and yield.”
Weed control is a key element of productive grassland farming and it is important herbicide applications are effective, made safely and with care for the environment.
Introducing a planned control programme for common weeds such as docks and thistles will easily pay for itself with a return on investment of up to 14 to one, says Mr Bishop. However, timing of herbicide is critical to achieving return on investment, along with choice of product to maintain clover-rich swards. 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 2 to 3 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 – before the first grazing.
“In established and permanent grassland, it is important farmers assess weed pressure as soon as grass starts to grow in spring. If they are to achieve a significant return on investment, then early assessment allows time to prepare, choose the right product and plan for timely application, either using onfarm resources or getting in a contractor to do the job.”
Planning and attention to detail are also top of the agenda for weed control as far as Dr Simon Pope, Wynnstay crop protection manager, is concerned.
He says: “Attention to detail is critical. In many of the cases where farmers have concerns about a lack of efficacy, it’s about getting the basics right, reading the label and following the recommendation for application. When you get the details right you will get more benefit and, of course, the product costs the same whether it’s applied well or badly.”
Planning ahead is another key consideration as far as Dr Pope is concerned. He says: “Waiting until weeds become a problem is too late to ensure effective control. By knowing where the problems are on the farm, getting everything lined up ready and applying once conditions are right it is possible to achieve the appropriate level of control.”
One of the fundamental principles for control of perennial weeds which is not always appreciated as far as he is concerned is the need to make sure that a lethal dose is applied which kills-off the root system. Many grassland weeds have large root systems, if the dose applied is sub-lethal then they will simply re-generate and the whole process will have been a waste of time.
Dr Pope says: “To be successful you need to apply the right product at the right rate under appropriate conditions. There needs to be sufficient leaf area on the target weed, for instance docks need to be 10 inches across. In terms of the right conditions, the plant needs to be in active growth so it will absorb the product and pump it to the root system. This means you are looking for a period of good conditions both before and after the treatment.”
Another important area flagged up by Dr Pope is the need for weed control in new leys. “I don’t think enough thought is given to planning weed control ahead of time when re-seeding,” he says.
“When the conditions are right for grass seeds to germinate, then they are also right for weeds to flourish. Often the best time for herbicide application is during establishment. If weeds are sprayed at the 2 to 4 leaf stage it is possible to achieve 100% control, something which becomes increasingly difficult as the weeds become more established.”
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