Using clover to drive performance with reduced Nitrogen inputs

Past Event

Mon, 08 June 2020

6:00 PM - 7:00 PM


Join AHDB’s Grass and Forage Scientist, Siwan Howatson, and Helen Mathieu, Area Sales Manager at Germinal for a webinar looking at the use of red and white clover to improve performance.

The webinar will be suitable for beef, sheep and dairy farmers – there will be advice on how to assess clover content in your pastures and how to introduce clover to various types of existing swards.Whether grazed or conserved, white and red clover both provide a good source of protein in ruminant diets and have high intake characteristics.

Clover plants also fix nitrogen (N), so there is an added benefit of less artificial N fertiliser being required for grass growth. Clover is suitable for many systems, being drought-tolerant and very palatable for livestock.


The webinar will cover:

  • Benefits of white and red clover - comparative feed value and cost comparisons of production systems
  • Animal performance for beef, sheep and dairy systems
  • Clover establishment and management guidelines
  • How to assess clover content
  • Advice on introducing clover to various types of existing swards
  • Advances in clover breeding
  • Using the Recommended Grass and Clover List (RGCL)

The webinar will last approximately 35 minutes, with time for questions at the end.

If you can’t make the webinar, please still register, as it will be recorded and sent to you afterwards to watch in your own time.

Q&A after the webinar

  1. Do AHDB do a recommendation for Scotland?

The recommended list for Scotland is produced by SRUC as a technical note and the latest version is available here

 

  1. What is the net penalty of clover dominance?

If clover becomes dominant (>60%) through most of the season and little grass is visible, it can unbalance the sward. This may increase weed infestations, as there is less ground cover during late autumn, winter and early spring, when clover growth has slowed or stopped. The target 30% clover will not affect overall yield of ley. Under rotational grazing, swards with 30% white clover content can be maintained for at least ten years, with total sward DM yields reaching 10–11 t/ha per year.

 

  1. With limited clover safe sprays is it best to oversow red clover rather than direct establish?

Yes, over-sowing does mean less pressure but the under-sown crop may compete with the clover and it might be poorer than if it had been drilled.

  1. We are an Autumn calving dairy herd, that graze from March until September, silage excess grass and have sheep in during the Winter. Can we find a White clover that can cover all these field requirements?

Clover growth will be lower over the winter months and therefore a medium - large leaf clover would be beneficial for rotational grazing cattle and taking excess as silage as the clover will be actively growing during these months. If you want to look at best options for sheep, medium leaf clover can be used if rotationally grazing sheep but not recommended for set stocking.

 

  1. Does white clover get stem nematode?

Yes. Causes distortion of growing buds and young leaves and death of the plant. Not the same strains for white and red clover, so white clover can be sown between red clover crops to break the pest cycle.

 

  1. Could you top up with large white clover in a cutting mix?

 

Large leaf white clover is suitable for a cutting mix.

 

  1. Which white clover on list has stolons as well as rhizomes?

Rhizobium bacteria, which exist symbiotically within protuberances or ‘nodules’ on clover roots. The stolon is a store for carbohydrates and proteins and provides the ability for the plant to over-winter and regenerate in the spring.

 

  1. Would you use caucasion clover instead of white clover for intensive grazing on heavy land?

 

Once established, tolerates continuous heavy grazing and grows best on well-drained soils.

 

  1. Could you expand on the management of white clovers in sward in further years following establishment, e.g. weed control and choice /timing of sprays/clover safety?

 

Tips for management:

  • Assess stolon growth in the spring and treat as though the stolons are weak and vulnerable
  • Avoid excessive stolon damage from poaching
  • If clover content is too low, do not allow grass to shade it out. Make sure it is grazed frequently, or take the paddock out of the grazing rotation as surplus before the plants gets too mature
  • Keep grass at 4–6 cm over winter to protect stolons from frost damage
  • If clover content is too high, use intensive grazing or strategic N use to increase grass growth

Weeds:

  • Maintain soil fertility to ensure grass and clover can be competitive against weeds
  • If herbicides are needed, use a clover-safe product and only spray if clover plants are vigorous and well developed
  • Use a weedwiper to treat target weed species only
  • Involve a BASIS trained adviser
  • Appropriate certificates are needed for anyone using sprays on-farm and equipment (except knapsack sprayers) needs testing. This is part of the Sustainable Use Directive

 

  1. To have an effect on reducing GHG how much clover would you need to have in the sward?

To be able to reduce nitrogen applications (most likely one of the biggest influences of GHGs on livestock farms) then we say around 30% white clover in the sward – typically there is approximately half of what appears to be there, if you look at the slide with the images of predicting white clover content.  To make a significant difference, then you’d need a reasonable quantity in every ley of course.  The white clover will also increase intakes and lamb finishing times, it is also higher in minerals, and will improve the soil structure and fertility. Some more measurable than others!

 

  1. How much nitrogen does clover contribute to grass growth and how long does it take after sowing a new ley for this to start? I am finding that the grass in new leys, even 2 or 3 years old, looks hungry.

On average, a good grass and clover sward (30–40% of dry matter of clover) will give an annual dry matter yield equivalent to that produced from about 180 kg N/ha applied to a pure grass sward in the first year. It is often difficult to decide how much nitrogen will be supplied because the clover content can be very changeable from year to year and within a given season. Clover is particularly sensitive to nitrogen application during establishment. Nitrogen should not be used during this period. Applications of fertiliser nitrogen to grass/clover swards should be made with caution because any form of mineral nitrogen inhibits nitrogen fixation by rhizobia in the clover nodules. There is also a risk of the grass responding to the nitrogen and shading out the clover, which can reduce the percentage of clover in the sward. However, some nitrogen may need to be applied to grass/clover swards to encourage early spring or late autumn growth: 

  • Apply up to 50 kg N/ha in mid-February to early March if early grass growth is required
  • Apply up to 50 kg N/ha in late July or August if autumn grass is required.

Information on soil test results, and whether it’s a short or long term ley, would be needed to answer this question in more detail.

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