Reseeding event

Published 10 May 13

Repairing the damage after a wet year

At a recent DairyCo, EBLEX and BGS event, hosted by Lordswood Farms at Walk Farm in Somerset, farmers looked at repairing the damage after the wet year. Independent soil and grassland management specialist Chris Duller, John Morgan from Creedy Associates and Alan Lovatt from IBERS at the University of Aberystwyth all offered their advice....

Chris Duller - Do you need to reseed?

  • Old swards perform mid season when the going is easy but drastically under perform in the early spring and autumn
  • Young leys respond better to nitrogen, so apply where you get the response
  • Last year very wet conditions lead to poaching damage, then soil damage, and so less ryegrass and more weeds
  • Rectify soil damage and understand soils film - Google DairyCo TV.
  • 70% grass seed sold is cut and graze, so by this definition we are to an extent diluting what we could potentially have if we grew mixes for cutting or grazing. The message being use the Recommended Grass and Clover list to get what suits you
  • £200 an acre to reseed - return on investment 1- 2 years!
  • Target for 70% ryegrass swards is 10t Dm/h or more, but if the same sward is full of other species and the soil is compacted, the top you may get is 8t DM/h or less
  • Compaction and very wet conditions = no worms. No worms mean poor soil activity and a build up of thatch at the sward base. This will lead to the thatch rotting and smelling, and the cows much less likely to achieve a good residual
  • If slitting / aerating - do the conditions allow it? There is no point slitting if it is too wet and the slitting smears the soil. The point of slitting is to aerate the soil and get oxygen into the soil and increase the flora and fauna to improve soil health. Should slit 2-3 acres an hour.

John Morgan - Decisions around reseeding

  • Reseeding £200/acre but 35% more yield first year and the next 4-5 years 10% more yield, so great return on investment
  • Germination - the land the group looked at was wet and warm enough and good soil contact with the seed had been achieved
  • Drilling grass not so deep and nice tilth on the surface and larger structures below are the aim
  • After all the wet weather we've had heavy soils are still vulnerable so too much traffic will cause compaction, and thus reduce the effectiveness of the reseed, so be careful!
  • Soil chemistry - must be right for germination so soil test
  • £1000's can be spent on fertiliser but unless you know the soil analysis this is potentially a guess
  • Soil tests are cheap so test a quarter of the farm a year and at best half the farm a year
  • Simple soil test P and K pH = £10. Lots of fields in UK pH 5.5 when they should be 6.5. At pH 5.5 nitrogen is half as effective as at 6.5, so get soil right
  • Clover is also vulnerable to poor P and K
  • Phosphate is key in root development and muck and slurry are a great source of phosphate
  • So a decent dose of 25t/hectare is great, don't overdo it though
  • 80% of P and K in feed goes through the cow back to the soil. So if you are not selling crops, and exporting the P & K this way, then if your indices are good you should be returning it back to the soil and should not have to buy in much. Soil test to check and confirm
  • 10% clover gives 50 Kg N / Ha / year, so 30% gives 150 kg N
  • If drilling grass clover mix fill the drill in the field, not in the yard and drive, so that the seeds do not settle out and you get a good mix
  • Reseeding timing - August is best, September is OK but October is too late - too risky
  • Do not cut seed rate it is false economy. £65/acre for seed, or thereabouts, in the life of the sward is a small cost. Cutting this will have far greater implications on sward life productivity and persistence.

Alan Lovatt  - Grass varieties

  • Use the Recommended Grass and Clover Lists as the varieties are trialled and tested independently and are consistent
  • Decide what you want from a reseed and then select species and varieties that do the job
  • Plant breeding has improved modern varieties in terms of yield and quality. As an example S23 from 1996 has 25% lower yield than modern varieties as well as better D values.
  • Diploids have 2 chromosomes and Tetraploids have 4 chromosomes
  • Tetraploid advantages - higher sugar levels generally than diploids, better disease resistance, palatability and winter hardiness. But they have fewer tillers so are actually more prone to poaching and they don't last as long as diploids
  • Diploids give persistence and ground cover
  • Diploid Italian lasts longer than a Tetraploid Italian
  • Festuloniums - ryegrass X fescue (fescue gives winter hardiness and drought resistance)
  • The different crosses can give very different results/characteristics so do your home work so you are getting what you want. They can also be perennial or Italian so check and pick for the job you want it to do.