Effective Weed Control- the Key to Driving ROI When Re-seeding

Achieving a significant ROI when reseeding grass is all about having the right set up in place, according to independent grassland consultant Dr George Fisher.

And a huge component of that, Dr Fisher adds, is a dedicated and effective weed control programme.

The right approach can yield an ROI of up to 20:1 as the reseed produces more grass energy to convert into milk compared with a permanent pasture.

Realising this, however, will rely on a rigorous approach to killing weeds before cultivation, and stopping seedlings taking hold once the new grass has been drilled.

Two Stage Process

Brent Gibbon, Nufarm’s grassland specialists, says that for autumn reseeds, a weed control programme is best implemented in July and August and consists of two stages – sward destruction and post drilling.

Sward destruction

The best start to any reseed is the complete destruction of the old sward before cultivating, Mr Gibbon says. But this often can’t be achieved using glyphosate alone.

He said: “Weeds such as Docks, Nettles and Thistles, together with cloves and volunteer brassicas will frequently survive a straight glyphosate spray and cause problems in the new sown ley.

“One solution to destroying these weeds and ingressing species is to use Kyleo, a combination of glyphosate + 2,4-D. This novel product will control the “difficult” perennial weeds along with all the old grasses.

“Once the old sward is showing signs of dying off, usually in just a few days, ploughing can then take place. The time between application and drilling will range from seven days if ploughed, to 28 days if direct drilled. Grass + clover mixes following ploughing can go in 14 days after application of the Kyleo.”

Post drilling

Weeds such as Fathen, Chickweed and Seedling Docks are the most critical weeds to control once drilling has taken place, Mr Gibbons said, otherwise they will soon out compete the young ryegrass. High populations of other weeds such as Charlock, Fumitory, Redshank and Mayweed can also cause problems.

For this, he recommends the use of phenoxy herbicides, including PastureMaster and CloverMaster, which form the basis of spring and autumn control mixes respectively.

“Controlling key weeds, in fact any weeds in a reseed is most effective at the two-leaf seedling stage – it makes for common sense compared to trying to kill a four feet high mature Dock plant next year,” says Mr Gibbon.
“Nufarm has developed some bespoke tank mixes for all reseed situations, so consult your advisor or retailer. Check product labels for full details.”

Growing ROI Yield

According to Dr Fisher, implementing an effective weed control strategy such as that outlined above can yield an ROI of up to 20:1.

He said: “Over the first five years, and compared to an old permanent ley, a reseed can produce enough utilizable grass energy per ha to make an extra 34,000 litres of milk. At 28ppl that’s worth £9,520 – around £20 back for every £1 spent. If the extra energy is used to replace concentrates, then over the five-year period, the extra energy is equivalent to 16 tonnes of bought-in concentrate feed – an 8:1 ROI.”

Reseeding grass brings a range of different benefits beyond the increased availability of usable energy. Table 1 outlines those key benefits compared with a permanent ley.

But, as Table 1 reveals, it’s not just the extra energy that contributes to the high ROI; there are a range of benefits that a reseed can bring.