Choosing the right mix

Published 23 August 10

To consistently grow lots of high quality forage and to ensure that grass is genuinely the cheapest feed, it is vital to have a programme of regular reseeding.  As reseeding is an expensive operation (£400/ha) it is important that you select a high quality seed mixture that matches exactly your requirements.

Selecting the appropriate mixture needs a bit of thought and planning. There are lots of permutations to think about; Italians, hybrids or perennials? Lates or intermediates? Diploids or tetraploids? What about a bit of Timothy? What about white clover, or even red?

A seed merchant that is a member of the Grass Levy Scheme and has access to all the NIAB recommended list data will be well placed to help you make all these decisions. The more information that you can provide them with the better suited your mixture will be. So think carefully about the following:

  • How long do you want the mixture to last?
  • Is the mixture for cutting or grazing - or both?
  • How many cuts and when will the cuts be taken?
  • What are your silage targets (yield/quality)
  • Rotational or continuous grazing?
  • When would you hope to turn out/house?
  • Will there be winter sheep?
  • Soil type
  • Altitude/aspect of the field
  • Are there any particular risks with the field such as frost pocket, winter flooding, thin soils or steep slope?
  • What's the history of the field, have you had weed or disease problems in the past?

The one thing not on my list is price. The expensive part of reseeding is the cultivations and sprays. There is maybe about £6 or £7 between a top quality mixture and a very average one and you will easily see the difference in cost back in better yields, persistency and higher quality.

For a seed merchant the easiest task is putting together either a silage only mix or a total grazing mix. The more things you want a mixture to do the harder it becomes and the more compromises have to be made. Putting together a cutting and grazing mixture that you want to fill the clamp, and keep summer grazing quality, and has to contend with winter sheep, and you want to last eight years, and you want under £40/acre - that's where the problems arise!

Short term silage leys are easy, a mix of two or three Italian ryegrass varieties, which all head within a few days of each other. Varietal differences are mostly concerned with disease resistance, mid-season digestibility and spring growth characteristics. So all the seed merchant has to do to formulate your mixture is consider when you plan to cut, what your targets are in terms of yield and quality and whether your site posses any problems with disease risk or drying up in the summer.

Longer term silage leys need a bit more care and attention, normally with a mixture of hybrid and perennial varieties with heading dates ideally within a ten day window. This year I have seen plenty of silage leys with too wide a spread of heading dates. First-cut came off in mid-May with decent quality but any late varieties in the mixture hadn't reached heading - so promptly started to head about a week into the start of second cut growth.

Grazing leys will normally be based around diploid perennial varieties to give good ground cover and persistency with maybe 20-30% tetraploid varieties to boost yields and give the sward a bit of structure. Varieties are selected on yield and quality and heading dates matched to your grazing demands through early season and the expected lifetime of the ley. Very early rotational grazers may also think about a few kg of hybrid in the mixture.

Formulating seed mixtures will always be a balance of following basic rules, selecting varieties to match requirements based on NIAB information - and a bit of personal preference and experience of the seed merchant. Don't underestimate the value of your seed merchant's experience and knowledge, but most importantly don't miss out on the wealth of trial data that is supported by the NIAB scheme, make sure you buy from a NIAB levy payer.

Download the Recommended Grass and Clover List or call DairyCo publications to order: 02476 478702.