Integrate herbal leys into a rotation to reduce emissions

Integrating herbal leys into the farm’s rotation can play an important role in improving soil health, reducing the need for synthetic fertilisers and supporting a more sustainable and low-carbon farming system.

Herbal leys, also known as multispecies swards, are a carefully designed mixture of grasses, legumes and forbs. These leys can contain anywhere from 3 to over 20 species. Research suggests that leys containing at least 6 different species deliver the full range of ecological benefits, supporting the health of both livestock and the land.

Herbal leys can:

• Enhance pasture performance
• Reduces reliance on fertiliser
• Provide high-quality feed for livestock
• Improve livestock health and productivity
• Increase resilience to weather extremes (e.g. drought) and pests

However, success depends on careful species selection, suitable site conditions, and appropriate grazing and soil fertility management. Tailor mixtures to your specific goals and environments and monitor ley performance over time to adapt management accordingly.

• Deep-rooting herbs improve soil porosity and water infiltration, making soil more resilient to drought and compaction
• These deep-rooting species may contribute to improved soil structure and organic matter dynamics, potentially enhancing carbon storage in some contexts. However, the net impact on soil carbon sequestration depends on management, previous land use, and soil type

• Nitrogen (N)-fixing legumes in herbal leys (e.g., clover, vetch and lucerne) fix atmospheric N into the soil and reduce reliance on synthetic fertilisers which are associated with nitrous oxide (N₂O) emissions
• Less fertiliser means lower input costs and reduced environmental impact associated with the manufacturing of the fertiliser
• Deep-rooting herbs improve water infiltration, enhance drought resilience, reduce runoff, erosion, and nutrient leaching, which all contribute to improved water quality and better system resilience
• These plants draw moisture from deep within the soil and break up compacted layers, helping other plants establish deeper roots and store more carbon, slowing its release into the atmosphere
• Some species, notably clovers, vetch, lucerne, sainfoin and bird’s-foot trefoil, enhance soil fertility therefore less inorganic N inputs are needed. Depending on the species choice and grazing management, herbal leys are known for their persistency with species like timothy thriving over several years

• Herbal leys offer valuable benefits for livestock health. Species like sainfoin and chicory contain condensed tannins which have been shown to reduce faecal egg counts and parasitic worm burdens in ruminants
• These species may also improve protein use and provide important trace minerals such as calcium, copper, and selenium contributing to better animal health
• Extended grazing system at both ends of the year

• Higher plant diversity and root biomass from these species contribute to the overall resilience of the farming system
• Many herbal leys can persist for 4–5 years or more, although, their botanical composition may evolve over time. Species, such as timothy and cocksfoot, are particularly persistent, while others like chicory or plantain may decline after 2–3 years without reseeding or careful grazing management

Farmers across the GrassCheckGB monitoring network measure their grazing platform weekly throughout the grazing season and submit regular samples for grass quality analysis, providing a dataset all farmers can refer to for insights.