Controlling Weeds in Grassland
After first cut silage or when paddocks have been topped is an ideal time to get weeds under control especially this year due to the excellent growth pattern.
Control of weeds in grassland is an ongoing issue on most farms and if good control has not been achieved at the reseeding stage, it can become a relentless challenge. Docks in poor grassland can account for up to 60% ground cover and take as much fertility from the ground as grassland. Docks in silage can affect fermentation and reduce the silage quality.
Weeds in grassland compete for space, light, nutrients and water and are unpalatable to stock. There are some key management tips that can help with grassland weed control, such as avoiding poaching of ground, avoid spreading large quantities of slurry and regular reseeding.
What products to target different weed species with:
The best control is identifying the weeds that are prevalent in pastures, and applying the right product in the right quantities. The following table should help:
|Weed problem||Solution||Grazing interval||Water volume|
|Docks & Chickweed||Doxstar , Hi-Load or Reaper/Binder||7 – 14 days||300-400 L/ha|
|Docks, Thistles, Nettles, Buttercups, Dandelions||Forefront or Thrust||7 – 14days||200-300 L/ha|
|Thistles||Thistlex , MCPA or lupo||7 – 14days||200-400 L/ha|
|Docks, Nettles & Thistles||Pastor Trio (NEW), Lupo, or Thrust||7 – 14 days||300-400 L/ha|
|Ragwort||D50,Thrust or Lupo||2- 3 weeks||300 – 400l/ha|
Identify the field or fields that are in the most urgent need of reseeding usually obvious from underperformance or if infested by weeds. In optimum growth conditions, it should have been very obvious which paddocks were underperforming and not growing grass efficiently.
Now is also the perfect time to get your soil tested if no recent samples have been taken. It is pointless reseeding if problems in soil fertility are not rectified or known beforehand. With the correct application of lime, phosphorus (P), and potassium (K) grass seed will establish quicker and grow better.
Steps to a successful reseed
There are a number of crucial steps to a successful reseed and this starts with spraying off the old sward with the correct rate of a Roundup product such as Roundup Flex or Powermax. This will kill weeds such as docks, thistles, and weed grasses, giving the new seed the best possible opportunity to establish without competition from existing species. Make sure there is plenty of fresh leafy growth on all the grasses before spraying off to achieve the best results.
In terms of ground conditions, always aim to develop a fine, firm and level seedbed. If the tilt is not very fine, grass seed will be lost or fall too deep where it cannot germinate. After cultivating the soil surface, the seedbed should be rolled before sowing to prevent the seed being buried too deep into the cultivated soil.
Earlier the better as autumn approaches
If at all possible, get your grass seeds established in August and growing before growth rates drop. This will also allow for an early grazing opportunity before the winter months, allowing the new pasture to tiller out. Early sowing will also give more time to spray the reseed for weeds which is the most important spray and generally gives best long-term control of the main problem weed.
Grass seed mixtures
At Connolly’s RED MILLS we put substantial effort into formulating our grass seed range. We select the best varieties for our mixtures using all the leading cutting-edge research and trial results coming from the Department of Agriculture variety trials and from Teagasc. Varieties will perform differently depending on your soil conditions and management; grazing or silage.
Reseeding is a worthwhile investment which will easily pay for itself within 18 months to 2 years. Our message to farmers is to invest wisely ensuring you maximise the performance and value of your new reseed. For more information or assistance, contact the RED MILLS agronomy team.