Multispecies Swards

Ryegrass-only swards are input-heavy and weather-sensitive.
Multispecies swards improve soil, cut inputs, and boost resilience to drought and climate change.

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The Climate Issue

Most dairy pastures in Europe are dominated by ryegrass. While productive, ryegrass has shallow roots, depends heavily on fertiliser, and struggles in drought.

These monocultures require high nitrogen inputs, which drive up emissions of nitrous oxide and ammonia. They also degrade soil over time, reducing organic matter and biodiversity.

As climate patterns shift, ryegrass-only swards become less reliable, especially in dry summers and on lighter soils. A more resilient, low-input pasture system is needed.

The Solution: Multispecies Swards

Multispecies swards (MSS) mix ryegrass with legumes and herbs like white clover, red clover, plantain and chicory. These species have different root depths, nutrient needs, and growth patterns, working together to improve pasture performance.

Legumes fix nitrogen from the air, reducing fertiliser needs. Herbs like plantain improve soil structure and reduce nitrogen losses in urine. Deeper roots also boost drought resistance and carbon storage.

MSS maintain yield with 50–70 % less nitrogen fertiliser. They also support animal health and increase biodiversity.

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Key Benefits when using Protected Urea

Lower Emissions

With lower fertiliser needs and improved nitrogen cycling, MSS reduce direct and indirect emissions, especially N₂O and ammonia.

Resilience

MSS are more drought-tolerant than ryegrass. They keep growing in dry conditions, protecting milk yield when rainfall is scarce.

Animal Intake

High-quality forage with better palatability and minerals improves dry matter intake and can enhance milk solids.

Impact of implementing Multispecies Swards

Multispecies swards (MSS) offer a practical, soil-focused solution to improve climate performance without sacrificing productivity. With good establishment and grazing management, MSS outperforms conventional swards in nitrogen use efficiency, drought resilience, and soil health. Initial reseeding costs should be factored in

Research from Teagasc and Farm Zero C shows MSS can:

Cut synthetic nitrogen fertiliser by up to 90 kg/ha
Lower GHG emissions by 4–9 % across the grazing platform
Improve drought tolerance and soil structure
Maintain or improve milk solids per hectare during dry or variable years

The table below shows the impact of adopting MSS across different portions of the grazing platform in Irish dairy systems, with fertiliser savings based on reduced nitrogen use and an assumed CAN cost of €88/ha.

Scenario	Area under MSS	Fertiliser Savings / 50 ha	GHG Emissions	% GHG Reduction
0% MSS	-	-	0.960 kg CO₂-eq/kg milk	0% kg CO₂-eq/kg milk
50% MSS	25 ha	€2,200	0.916 kg CO₂-eq/kg milk	4.6% kg CO₂-eq/kg milk
100% MSS	50 ha	€4,400	0.876 kg CO₂-eq/kg milk	8.8% kg CO₂-eq/kg milk

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Considerations

Establishment

MSS require careful sowing. Best results come from full reseeds with low weed pressure, pH 6.3+, and good P and K indexes.

Grazing Management

Frequent grazing helps maintain herb and clover content. Avoid overgrazing or long rest periods to support species balance.

Persistance

Some herbs may fade after 3–4 years. Reseeding or oversowing may be needed to maintain diversity and performance.

Implementation

MSS can be rolled out gradually, field by field. With good establishment and grazing, they deliver long-term performance and climate benefits. Follow these steps to start.

1. Choose the right mix. Use a balanced seed mix with ryegrass, red and white clover, plantain and chicory. Avoid aggressive ryegrass dominance.

2. Reseed carefully. Sow into warm, moist soil in spring or early autumn. Maintain high soil fertility and avoid compaction.

3. Manage grazing. Start grazing when covers reach 1 200–1 400 kg DM/ha. Rotate frequently and avoid letting covers exceed 2 000 kg to preserve herb content.

Behind the Research

ODOS Tech was founded by Cian White and Alejandro Vergara, two sustainability specialists with deep expertise in agricultural climate action.

Alejandro (left), a PhD in environmental engineering from University College Dublin, helps farmers measure their carbon footprint and implement mitigation strategies to reduce their impact. Cian (right), a researcher at Trinity College Dublin with a PhD in ecology, works on restoring nature to increase biodiversity on farms using satellite imagery to monitor habitats.

Together, they helped lead the carbon and nature-based work for the Farm Zero C project at Shinagh Farm, one of Europe’s first net-zero dairy pilots. In 2020, they launched ODOS, a platform that built smart, science-based tools to help agri-food businesses protect the environment and restore nature.

Research

Teagasc Grass Trials

Teagasc trials show MSS maintain yield with 100 kg less nitrogen per hectare. Animal performance is equal or better than ryegrass swards, especially in summer.

Farm Zero C at Shinagh

Shinagh Farm introduced MSS to improve drought resilience and soil health. Fertiliser inputs dropped, and pasture quality remained high during dry periods.

EU and CAP Support

MSS are included in several CAP eco-schemes due to their co-benefits for biodiversity, emissions, and water quality. Many governments now offer incentives for adoption.