Peak district herbal ley silage trial

Can herbal leys produce high-quality silage in upland livestock systems? To help answer this question, we worked with Natural England, the University of Reading and Corteva Agriscience, alongside six Peak District livestock farms, to explore how herbal ley silage performs under real farming conditions.

This knowledge exchange project focused on practical farm management rather than tightly controlled research plots. This means the findings are directly relevant to farmers considering herbal leys within their forage systems.

Interest in herbal leys continues to grow as farmers look for ways to improve farm resilience, support soil health and reduce reliance on purchased nitrogen fertiliser.

However, there’s limited information on how these diverse swards perform when conserved as silage, particularly in upland areas.

The project explored:

• The silage yields and quality that herbal leys can achieve in upland systems
• How first, second and third cuts compare
• Whether a homofermentative silage inoculant improves silage quality
• How NIRS forage analysis compares with laboratory wet chemistry testing
• Practical lessons around wilting, tedding and harvesting

The trial involved six farms across the White Peak area of the Peak District. Together, they managed 42.9 acres of herbal leys and produced 716 silage bales across first, second and third cuts.

The sites represented real commercial livestock systems on free-draining limestone soils, with annual rainfall ranging between 929 mm and 1,122 mm during the study year.

Most farms followed a similar approach:

• Wide mowing without a conditioner
• Around 24 hours of wilting where conditions allowed
• Minimal crop handling
• Prompt baling and wrapping

To assess the value of additives, around half of the bales received a homofermentative inoculant, while the remainder were left untreated.

Twenty-two representative samples were collected and analysed using both laboratory wet chemistry at the University of Reading and commercial NIRS forage analysis.

First-cut yields ranged from approximately 1.6 to 3.4 tonnes of dry matter per acre.

While yields generally declined in later cuts, forage quality improved through the season.

The results show that herbal leys can produce acceptable silage yields in upland livestock systems, especially where nitrogen inputs are low or supplied through organic manure and slurry.

One of the clearest findings was the difference in forage quality between cuts.

First-cut silage tended to have:

• Higher fibre levels
• Lower crude protein concentrations
• Lower metabolisable energy

In contrast, second and third cuts generally had:

• Higher crude protein levels
• Lower fibre concentrations
• Improved fermentation characteristics
• Drier, haylage-like forage

The analysis showed that cut timing and growth stage had a significant influence on silage quality.

The trial found no significant improvements in dry matter, energy, crude protein or fibre content from using the inoculant.

There was a small trend towards improved fermentation, including slightly higher lactic acid levels and lower pH values.

However, these differences were not large enough to demonstrate a consistent benefit under the conditions of this study.

Overall, successful silage production was more strongly influenced by harvest timing, wilting and storage management than additive use.

A key learning was the difficulty of achieving the recommended 35–45% dry matter target. In fact, 88% of samples fell outside this range, with most below 35% dry matter.

A 24-hour wilt was often insufficient, particularly for first-cut silage in upland conditions.

While lower dry matter did not appear to affect nutritional value, wetter silage can increase risks around storage, preservation and handling.

Longer wilting periods, and light tedding where appropriate, may help achieve target dry matter levels.

Read the full report for detailed results, practical recommendations and lessons learned from participating farms across the Peak District.