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Why grow a root crop?

Sector News Sector News8-7-2019
  • Improved profitability
  • Reduced reliance on purchased feed
  • Flexible cropping options
  • Extended grazing season
  • Outwintering options
  • Low inputs

Root crops and brassicas offer a highly palatable fresh feed which are high in digestible fibre, sugars and protein. The table below provides some guide values.

Species Fresh Yield (Tonnes/ ha) Dry Matter (Tonnes/ ha) Crude Protein (%)


Grazing days / ha Sheep 7.5Kg/Day Grazing days / ha Sheep 10Kg/Day Grazing days / ha Dairy or Beef 22Kg/2-3 hour period
Kale 60-80 8 - 12 16-17 10 – 11.5 6,000 4,500 2,045
Stubble Turnip 40-50 6 - 12 17-20 10 - 12.5 4,000 3,000 1,364
Forage Rape 24-35 3 - 6 19-20 10 – 11 3,500 2,625 1,193
Swede 70-90 7 - 10 10-11 12  - 13 8,000 6,000 2,727

It is important to introduce stock slowly to the crop and balance the ration with effective fibre. Choice of location should allow stock to be grazed back onto grassland once they have eaten their allocation and the crop should be grazed behind an electric fence to ensure that utilisation remains high.

Break Crops

Root crops are valuable as a break crop between grass leys due to the risk of frit fly which can cause considerable damage to autumn grass reseeds or even devastate a new ley. Frit fly lay their eggs on or near grass plants. On hatching the larvae tunnel into the centre of the grass plant eating out the heart and killing the whole plant. Larvae can also migrate up from the remains of the ploughed decaying sward to infest the new ley. Direct drilled (slot seeded) reseeds can be particularly at risk as the larvae find it easy to migrate from the decaying vegetation to the seedlings often in the same slot. Breaking the cycle by establishing a fast growing summer break crop, the frit fly is unable to continue its life cycle.3

Most at risk from frit fly damage:

  • Ryegrass leys, particularly Italian though perennial also suffer significantly
  • Autumn or late summer sowings especially crops sown in mid-August
  • Direct drilled reseeds
  • Grass to grass sowings
  • Grassy stubbles
  • Fields with a previous history of damage.

If possible, leave a long gap between ploughing and reseeding grass, ideally 6 – 10 weeks but a minimum of 2 weeks to reduce the frit fly source.

Afbeelding: roots graph 8.7.19

Find out more....

For more information contact your local forage specialist or call 0330 678 1200.

Link: 61907