Building Value from Herbal Leys: Making SAM3 Work for Your Farm

Herbal leys under SAM3 can deliver far more than an SFI payment. With the right species mix and management approach, they can improve forage resilience, soil function, and long-term productivity across your farming system.

Why herbal leys need careful planning

Interest in herbal leys continues to grow, driven by the Sustainable Farming Incentive (SFI) and increasing recognition of their environmental and livestock benefits. Not all herbal leys deliver the same outcomes, and selecting a low-cost seed mix simply to meet scheme requirements can limit the wider value they bring to your business.

According to Agrii grass, roots and environmental seeds manager Adam Simper, success depends on choosing mixtures that fit your farm system rather than treating SAM3 as a compliance exercise.

When specified correctly, herbal leys can strengthen forage supply across the season, improve soil structure and organic matter, and support long-term productivity alongside environmental gains.

For many producers, herbal leys represent a new area of grassland management. The increasing number of mixtures available, combined with a wide range of claims about performance, can make decision-making difficult. The key is understanding how different species combinations will integrate with your existing livestock and grassland management.

Matching mixtures to your farming system

Herbal leys typically combine grasses, legumes and herbs, with their value coming from the diversity of species within the sward.

Deep-rooting plants can access nutrients and moisture from lower soil layers, helping create a more balanced and mineral-rich forage. This forage can be used for grazing or conserved as silage depending on the system.

Below ground, varied rooting depths help improve soil structure, increase water infiltration and support nutrient retention. Legumes contribute by fixing atmospheric nitrogen, reducing reliance on inorganic fertiliser inputs while improving soil fertility.

Greater species diversity can also support biodiversity and beneficial insects while helping disrupt pest cycles within grassland systems.

These benefits depend on choosing a mixture suited to your soil type, livestock system and grassland management approach.

Understanding SAM3 and CSAM3 requirements

The SAM3 action focuses on establishing herbal leys to improve soil structure, increase carbon capture and enhance soil biology and fertility. Eligible land includes arable land as well as temporary and permanent grassland.

Under the scheme, producers can claim £382 per hectare.

The CSAM3 offer requires a mixture including at least one grass species, two legume species and two herb species.

Guidance also recommends limiting inorganic nitrogen use to around 40 kg N per hectare annually.

Earlier voluntary guidance encouraged greater diversity, suggesting mixtures including five grasses, three legumes and five herbs.

Typical species used in herbal ley mixtures include ryegrass, timothy, fescues, cocksfoot, festulolium, red and white clover, birdsfoot trefoil, chicory, plantain and yarrow.

Establishment is normally required by early autumn within the first year of the agreement, with the ley maintained for at least two growing seasons to deliver soil improvement benefits.

Choosing the right herbal ley approach

Herbal leys can be designed to meet different objectives within your farming system.

Some mixtures prioritise forage production for grazing livestock, while others focus on silage production, drought resilience or increasing species diversity within existing grassland.

Grazing-focused mixtures are designed to produce consistent, high-quality forage while maintaining sward density and resilience during dry conditions. Cutting-based mixtures may avoid species such as chicory, which can become woody if allowed to mature and create challenges when baling and wrapping silage.

Where existing swards need improvement, overseeding options can increase the proportion of legumes and herbs without full reseeding. Successful overseeding depends on removing thatch to ensure good seed-to-soil contact and allowing sufficient light for seedling establishment. Avoiding nitrogen applications during early establishment helps reduce competition from existing grasses.

Management matters as much as mixture choice

Establishing a diverse sward is only part of the process. Management decisions determine whether herbal leys deliver their full value.

Under SFI guidance, leys should be maintained through grazing or cutting and left undisturbed for a period during late spring or early summer to support pollinators.

Rotation is possible, but the ley should remain in place long enough to improve soil structure and organic matter. Overseeding may be required if establishment is uneven or species decline.

Inputs must also be carefully managed. Both SAM3 and CSAM3 restrict pesticide use, and herbicides should only be used for targeted weed control. Nitrogen applications must remain limited to maintain the benefits of legume nitrogen fixation.

Keeping accurate records, including seed receipts and management actions, is essential for scheme compliance.

Delivering value beyond the scheme payment

Herbal leys can play an important role in improving livestock nutrition, supporting soil health and reducing fertiliser reliance. When integrated properly into a rotation, they contribute to forage resilience, biodiversity and long-term farm productivity.

The most successful herbal ley systems are those designed around the needs of the farm rather than the requirements of the scheme alone.

By understanding how species selection, establishment and management work together, you can ensure herbal leys deliver lasting value across your farming business.

Speaking to an Agrii specialist can help you identify the right mixture and management approach to achieve your objectives.

Note: This article reflects SFI guidance available as of December 2024. Scheme rules may change, and producers should always check their individual agreements.