Managing Grass Swards

Weather patterns are changing, and intense rainfall and dry spells are becoming more common. This year we have experienced an unprecedented dry spring, in contrast to the persistent rain of 2024. We can’t predict when these extremes will hit, but it’s clear they are making farming more challenging than ever.

Rain has arrived for most by now, but it is important to remember that there will be a period of recovery for those crops and swards affected by the earlier dry spell and perhaps already some forage deficit concerns for the coming winter. The key priority over the coming months is to look at how we respond to the dry weather with our grassland management.

In some areas, pastures were burning off at alarming rates, more rapid on shallower soils with little grass cover. Although these areas have now had rain, recovery will not be overnight and the challenge ahead is managing grass quality and quantity as soils reset.

When grass is grazed below the target height of 4-5cm the plant must use more energy from its root reserves to produce leaf area to then photosynthesise, slowing down recovery and reducing root growth. This also places significant stress on the plant. Moving stock off fields at target residual 4-5cm will ensure the plant is given time to recover. If possible close off the fields worst affected as livestock will continually seek out the freshest grass leaves, slower recovery further.

Affected swards will take weeks to recover so accept that supplementary feed will be needed to meet the feed demands of livestock before there is enough grass to fulfil the demand. However, in this weather livestock are generally quite content and will need a lower volume of grass due to the higher dry matter content.

A grass plant’s default response to stress, such as drought, is to flower and set seed. This poses a challenge in providing quality forage for grazing livestock or making high quality leafy silage. As swards recover topping of pastures to remove the stemmy material will help to reset residuals. Rotational grazing to reduce the amount of selective grazing and provide the rest which will give those developing leaves time to grow. There is also value in resisting the urge to top immediately to leave a layer of protection for the soil, but this must be balanced with grass growth rates, pasture quality and feed demands.

Synthetic fertiliser or organic manure application over the previous few months will not have been taken up by plants with slow growth due to the lack of rainfall. Crucially this can lead to plants with excess nitrate levels which has the potential to cause problems in the fermentation progress, resulting in poor quality silage. The target level for grass at cutting is below 0.1% (1000 mg/kg fresh weight) nitrate-N. Use test strips for nitrates on farm, or by send grass samples to a lab for analysis, if you are unsure of grass nitrate levels.

The warmer, drier conditions combined with the additional stress from lack of rainfall has led to grass heading dates being earlier this year. This will affect silage quality and consequently have an impact on winter feed budgets. A change from 25% of a silage sward with seed heads emerged to 50% of the crop can decrease the metabolisable energy from 11.5 MJ/kg DM to 10.5 MJ/kg DM. Energy which will need to be replaced in the winter ration.

With this in mind it is a good idea to be preparing a feed budget now to assess your winter feed requirements to help with identifying any possible gaps early, allowing you to make informed decisions about how you meet forage demands and consider alternative plans.

Looking ahead we need to look differently at how we manage our grass and forage crops to adapt to our changing climate. Get to your soil types across your farms and how different soils respond to different weather and management. Most soil analysis will now contain a measure of the organic matter levels in your soil giving an indication whether the application of organic manures over several years is needed to increase the soil organic matter (SOM) levels and consequently that soil’s ability to retain nutrients and water.

Remember there is still funding available this year for soil analysis through Preparing for Sustainable Farming (PSF). Using lab analysis will help with nutrient planning to ensure crops have the fertility they need, when it is needed.

5 Top Tips

1. Remember following a period of drought, crops and grass swards take time to recover.
2. Supplementary feeding of livestock could be required while grass recovers to ensure feed demands are being met.
3. If possible close off fields from livestock worst affected to aid recovery.
4. Prepare a feed budget now.
5. Consider longer term grazing strategies in grazing management.

Useful Links

• Managing grass swards through dry conditions
• Climate resilience vlogs
• Feed budgeting
• A step by step guide to forage and feed budgeting
• Preparing for Sustainable Farming guidance

Lorna Galloway, Senior Consultant, Lorna.Galloway@sac.co.uk

Unearthed is the exclusive SAC Consulting members' monthly newsletter. Unearthed offers insights and tips from our experts on what we think is in store for farming and crofting in the coming months in order to protect and enhance your business.

Posted by Unearthed News on 17/06/2025