The £382 per hectare stewardship payment for herbal leys has beckoned many farmers with the promise of financial gain. However, this financial incentive can sometimes obscure important considerations. In this article, we explore the complexities of herbal leys in modern farming, shedding light on the potential pitfalls and emphasizing the need for thoughtful planning in their implementation.

Many farmers have been attracted enticed by the £382 per hectare stewardship payment for implementing a herbal ley, often overlooking potential downsides. This financial incentive has sometimes overshadowed other critical factors that should be considered before implementing the ley. It’s essential not to lose sight of fundamental stock management principles when establishing any ley, especially a herbal one.

Despite much of the current marketing portraying herbal leys as the ‘new, bigger, better sexier’ solution to increasing stock production and soil biodiversity, they are not a modern innovation. Back in the 1950s, the herbalist and naturopath Frank Turner described the herbal ley as his “fertiliser, merchant, food manufacturer and vet all in one” – a fitting description of the benefits a properly implemented herbal ley can provide.

Many farmers and growers have understandably been drawn to GS4-type leys due to the £382/ha stewardship payment they offer. Beyond the financial incentive, the potential to improve stock performance and reduce feed and fertiliser expenses is equally attractive.

The core idea behind the herbal ley is to establish a ley that not only nutritionally feeds the stock, but also invigorates and improve the physical soil structure and the soil microbial community.

Often, farmers request a ‘GS4 compliant mixture’ from their supplier without considering the ley’s longevity or how well-suited the GS4 species mixture is to their specific geography, altitude, and, crucially, soil texture. Another vital factor to consider is how appropriate the supplied mixture is for the grazing regimen.

If we consider the Government guidance for the GS4 mixtures, it states the following two stipulations:

1. Make sure that the seed mix sown contains at least five species of grass, four species of legume and four species of herb or wildflowers.

1.1 We must always remember that all domesticated stock is fundamentally designed to thrive by grazing on grass species. That grazing needs to be complemented with a proportion of legumes, herbs and forbes (herbaceous, but not woody, broadleaf plants that are not grasses) to enhance their ability to access extra trace elements, and in some cases carbohydrate.

1.2 With how the supply market is structured, the cheapest ingredient to supply of the five specified grass species will be ryegrass. But that might not be the most appropriate species for your environment as it is shallow rooted, and highly prone to dying in periods of adverse weather. Which then inevitably allows the legumes to proliferate to the potential detriment of the stock.

1.3 Query what the five grass species are, and if their rooting depth and feed value are relevant for your cropping situation.

1.31 Cocksfoot [1m root depth] This species can easily withstand mob grazing (once established) and has the same nutrition feed value as perennial ryegrass. It also extracts more copper from the soil than any other species. Prone to becoming ‘woody’ during stem-extension, so tightly of top to rejuvenate.

1.32 Timothy [0.75m root depth] Has a tiny seed, so only necessary to include a low rate. Excellent carbohydrate value.

1.33 Meadow Fescue [0.75m root depth] Tolerates both acidic soil and drought conditions particularly well.

1.34 Sheeps Fescue [0.25m root depth] Withstands grazing pressure well even though relatively shallow rooted, and crucially has evolved to proliferate Arbuscular Mycorrhizal Fungi in the soil to aid sward survival.

1.4 One of the biggest issues I regularly encounter is that the mixture simply does not contain a high enough proportion of appropriate grass.

1.41 Historically, to establish a viable sward grass seed rates are recommended to be at least 35 kg/ha. But the proportion of grass in most formulaic herbal ley mixtures is only 25 kg/ha. That rate doesn’t take much adverse weather to stress the grass and significantly reduce the productivity of the ley.

1.42 If we consider that it is reasonable to expect a 10% field loss from ‘field factors’ after drilling, then to only have a final viable establishment of 22.5 kg/ha (25kg/ha – 10%) is detrimental to stock productivity.

1.5 Often, the weather patterns in the months after drilling (particularly hot and dry) favour the legume productivity over the grass species. Which means that the stock has a higher than desired proportion of legumes to graze on. – See the ‘problems & solutions’ section later in this article.

2.2. Make sure the sward has a minimum 20 per cent cover of other legumes and herbs (not counting white clover, creeping buttercup, or injurious weeds). .

2.1 Fundamentally the inclusion of 2-2.5kg/ha of clover can increase the dry matter production of the ley by up to 1.5 T/ha. But only if the clover is still producing nitrogen.

2.2 It is important to consider the growth habit of the legumes and herbs to be included in the mixture to ensure that they complement the grass growth, rather than produce biomass that will shroud out the grasses. This is especially important during periods of adverse weather.

2.3 Give regard to the inclusion of Trefoils and Black Medic as they are both extremely long lived and provide nitrogen at a commensurate rate with grass growth but without shrouding out grass growth.

2.4 Red Clover (always considering the phyto-oestrogen properties of Red clover) is a useful addition to increase the feed value in any harvested forage.

2.5 Vetch species can be considered as they are leguminous. But their natural growth propensity is that they need warmth and a long day-length to germinate and thrive. Generally, this the weather patterns during an early spring drilling.

Problems I have encountered with herbal leys over the past two seasons, and possible solution to the problems.

These problems have largely occurred over the past few years because of the wet, warm springs that have favoured clover growth over grass growth. This was compounded by excessive periods of drought after the rain, stimulating (legume) leaf production over grass growth.

A Losing initial performance at turn-out as the rumens have not transferred onto forage rapidly enough.

A.1 After turn-out, it can take two weeks for the rumen microbial populations to adjust to grazed grass

B Bloat was the most common occurrence of death in yearling cattle.

B.2 Allow animals to self-regulate by offering readily available sources of roughage e.g., hay.

C Inappropriate mixtures for the environment, resulting in not enough (grass) fibre and significant gaps in the sward.

C.1 Ensure that the seed mixture drilled is appropriate for your environment and stock species.

D Mixtures with too much ryegrass, for the environment, and not enough deep-rooted grass species.

E Lambs dying within days of weaning.

E.1 Consider that it can take two weeks for the rumen microbial populations to adjust to grazed grass, so a ‘little and often’ initial introduction can help lamb transition to grazing on a herbal ley. Certainly, avoid putting lambs onto herbal leys when they are hungry as they will gorge on the herbal element of the ley.