Multi-species sward - Should you reseed or overseed?

Multi-species swards are a sustainable source of high-quality forage. As well as producing high yields of quality forage, sowing a multi-species can lead to significantly reduced N fertiliser requirement, increased animal performance and health.

With constant fluctuation in the price of inputs like fertiliser and feed many farmers are looking atmulti-species swards as an option to reduce their reliance on expensive inputs and increase their profitability.

Furthermore, multi-species swards produce a greater volume of quality forage in summerthan grass alone and incorporating them into the grazing platform can lead to a steadier supply ofgrazed forage throughout the year. Some farmers are even sowing these mixtures as a buffer against drought.

As the uptake of multi-species swards among dairy, beef and sheep farmers steadily grows, DLF receives many calls from farmers looking for advice on how to best implement and manage this type of sward.
 

Why Sow a Multi Species mixture?

• Multi-species swards can produce similar DM yields to perennial ryegrass swards at significantly lower rates of inorganic N fertiliser. This could be worth up to 6 bags CAN/acre per year.
• Multi-species swards are a source of highly digestible, high protein forage and can maintain their high quality throughout the growing season.
• The inclusion of warm-season species like chicory and red clover means multi-species swards have strong summer production compared to a grass sward.
• These deep-rooting species make the sward much more tolerant of drought than a grass sward.
• The inclusion of mineral-rich herbs provides a more balanced diet than grass alone with species like chicory also providing some anthelminthic benefits to grazing livestock.
• The use of multi-species swards compared to grass-only swards in agriculture can also provide a wide range of environmental benefits including:
  Reduced N2O emissions and nitrate leaching associated with reduced fertiliser use.
• Higher rates of carbon sequestration due to deeper root-depths.
  Enhanced biodiversity, particularly pollinators feeding on the variety of flowering plants in multi-species swards.

What Mixture to Sow?

When deciding on a mixture, soil type and local climate are important as some species are better suited than others to particularly wet or dry conditions.

Species suitable for wetter soils include timothy, birdsfoot trefoil and burnet, while species like cocksfoot, lucerne and chicory will thrive in light, dry soils.

Depending on your soil-type a mixture of the specialist species above and some all-rounders like perennial ryegrass, white clover and ribwort plantain would make for a very productive sward.

A diverse mixture of species means a more resilient sward to extreme weather events like drought

Should you reseed with Multi-species swards?

A conventional reseed will give the best results in establishing your new multi-species sward, but the following points should be remembered when sowing:

• Ensure soil fertility (pH, P and K) is adequate as per recommendations for grass swards.
• Address any weed issues with herbicide before sowing as an herbicide cannot be applied to a multi-species sward. This is crucial.
• Cultivate to form a fine, firm seedbed.
• Apply lime and seedbed fertiliser as required.
• Roll the seedbed before sowing to ensure it is firm.
• Seed can be direct drilled no more than 1cm deep or broadcast.
• Sow seed at a rate of 27-32kg/ha or 13-15kg/ac.
• Roll again! A firm seedbed and soil contact is vital for the small seeds of legumes and herbs.
• Allow 8 weeks before the first grazing to let herbs establish strong tap roots.

The similarity in the growth habit of herbs like plantain and chicory to common grassland weeds like docks, means that once these species get established, there is no space in the sward for docks and other broadleaf weeds. Small outbreaks of weeds can be spot-sprayed if necessary.

Oversowing to Diversify an Existing Grass Sward

Clover and herb species can also be oversown into existing grass swards to achieve the benefits of amulti-species sward. White clover, plantain and chicory should each be oversown at a rate of 1.5-2kg/acre. 

Stitching in with a seed drill will help ensure soil-seed contact which will improve germination rates.Remember, we want to allow light to penetrate the sward to reach the new seedlings and reduce competition from the existing sward.

• Oversow after a silage cut or tight grazing
• Roll to ensure soil-seed contact
• Graze lightly shortly after oversowing to knock back the existing grass

To find out more about multi-species swards or about the partner farms in DLF Ireland - click here 
 

Learn about Multi-species with DLF

Hosted by Dr Thomas Moloney, DLF Ireland, we cover the A – Z of multi-species swards from selecting the right mixture to grazing and silage management.