Can Multispecies Swards Increase Overall Grass Yield?

15th June 2018

This week in our blog we’re looking at the SmartGrass project between Teagasc, University College Dublin (UCD) and Agri-Food Bioscience Institute (AFBI) (2014- 2015). The aim of the trial was to assess the effect that a multi species sward would have on:

  • Production in DM/ha
  • Animal health
  • Biodiversity

A multispecies sward, as the name suggests, is a sward made up of more than one species of grass. The swards in the SmartGrass project were made up of the following species:

A mixture of these species was sown in 2014 to make up 4 different sowing mixtures of

  • Perennial Ryegrass (PRG) mixture
  • Perennial Ryegrass (PRG) and white clover mix (PGR WC)
  • Simple mix (6 species) 2 grasses, 2 legumes and 2 herbs (simple 90)
  • Complex mix (9 species) 3 grasses 3 legumes and 3 herbs (complex 90)

The 4 different swards where given 90 kg of nitrogen to the hectare (72 units/ac).They were then compared to a control of PRG receiving 250kg nitrogen per hectare (200 units/ac). (PRG 250)

The results of how the swards yielded are presented in table 1

Table 1 Total yield DM/ hectare for treatments

The results speak for themselves

PRG with clover had a yield of double that of PRG 90 and approximately 20% more than PRG 250. The clear trend is the more diverse swards yield more, straight monoculture swards at 90kg N/Ha

Lamb Performance

The study also looked at animal performance in sheep grazing the different swards. They looked at lamb growth rates and the effect the different swards had on the amount of times the lambs had to be dosed.

Table 2 The effect of sward type on Average Daily Gain (ADG) from birth to slaughter

Table 3 The effect of sward treatment on number of doses required per lamb

PRG, Perennial Ryegrass, PWC Perennial Ryegrass with Clover, 6 species mix (as above) and 9 species mix 9 (as above)

We can see from table 2 and 3, that as well as having yield benefits, lambs grew quicker with better ADG and needed less dosing for worms too. This represents a number of benefits to the farmer and the consumer.

Conclusions

So, what we are we to make of all this? Go out and plant all our grasslands to multispecies swards?

Not just yet I think. This is a great trial with fantastic results in yield, animal performance and animal health. However, they are done on a trial plot level so the results have to be taken with a pinch of salt. The results need replicated again at a bigger level and then on to farm level.

What I would take from them is:

  • Clover had the greatest effect of increasing yield (dm/ha) than other species. Increasing clover in our swards is a good thing from both a yield point of view and its ability to fix nitrogen. I would encourage the use of clover in swards.
  • The need for less dosing of lambs for worms is a big result. The use of medicines in animals is becoming a massive issue for consumers of food. Designing swards to reduce the use of animal medicines is a massive selling point for consumers.
  • As farmers we are all being encouraged to farm more sustainably. Sustainability can be thought about like a 3 legged stool, take a leg away and it falls over. The legs are,
    • People
    • Planet
    • Profit

The SmartGrass project has had a positive outcome for all 3 legs of the stool.

  • Less animal medicines
  • Growing more yield (dm/ha) of grass with less nitrogen inputs
  • Increased ADG of lambs eating grass, means more profit form the farmer.

A winner all around. On the grapevine I have heard this project is to be expanded, let's watch this space.

Another important aspect of growing well yield swards is soil nutrition, like sustainability soil nutrition is a 3 legged stool of Chemical, Physical and Biological aspects of soil. If you are interested in multispecies swards, talk to us at Devenish about our Soil Improvement Programme, so that you can ensure your soil is in the best position to grow the best multispecies swards on your farm.

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