Cilthrew Project Update - January 2025

Background and Summary

Forage availability and quality following prolonged periods of dry weather is a major limitation for Welsh pastoral farmers. Multi-species leys, owing to their diverse root structures and depths have demonstrated potential for increased drought tolerance in comparison to conventional leys. This farmer-led project investigated the herbage availability and quality of diverse sward mixes throughout the 2024 grazing season.

Treatments included three diverse sward mixtures, 1) perennial ryegrass and clover control (PRG+C), 2) 2 legumes and 3 herbs (L+H) and 3) multi-species sward (MS, 5 grasses, 3 legumes and 3 herbs) (Table. 1). Plots were established in September 2023 and lightly grazed by ewes with lambs at foot for management purposes in May 2024 before grazing by fat lambs from June-December 2024. All stock was excluded in December 2024 and plots were rested ahead of the 2025 grazing season.

Table 1: Composition of seed mixes (%)

    

PRG+C

   

L+H

  

Perennial ryegrass

Timothy

White clover

  

White clover

Red clover

Chicory

Plantain

  

87.5 

5.4 

7.1 

  

18.2 

27.3 

27.3 

27.3 

  

MS

    

Tall fescue

Perennial Ryegrass

Timothy

Cocksfoot

Meadow fescue

White clover

Alsike clover

Red clover

Chicory

Plantain

Yarrow

18.5

14.8

11.1

18.5

14.8

11.1

3.7

3.7

1.5

2.1

0.1

Grazing season 2024

Herbage availability was measured from June–December 2024 along with a snapshot of the chemical composition (CP, NDF, WSC, ash) of swards in July 2024 before grazing fat lambs. Although no prolonged periods of dry weather were observed in the 2024 grazing season, insights on sward establishment and management were made and the wider benefits of multi-species leys showcased at a knowledge exchange event for Welsh farmers. Further measurements will be made in the 2025 grazing season.

Results and discussion

During the 2024 grazing season no prolonged periods of dry weather or drought conditions were observed, instead the grazing season was abnormally wet. Nevertheless, the results provide an insight into the performance of the diverse sward mixes under abnormally wet conditions.

Under abnormally wet conditions, the L+H and the MS treatments had significantly more herbage biomass availability across the grazing season in comparison to PRG+C (p=0.043, Figure.1). This was most likely attributed to the botanical composition of the L+H and MS leys regarding the presence of species with large leaf areas such as chicory. No data on botanical composition were collected to support this, however such data will be collected in the 2025 grazing season.  

 

Figure 1: Total herbage biomass availability (kg DM ha-1) over the grazing season (June to December).

The chemical composition of the different swards was measured prior to grazing fat lambs to provide a snapshot insight of nutritional quality. The results are presented in Table. 2.

Table 2: Snapshot of the chemical composition of swards in July 2024, before plots were grazed by fat lambs.  

 

PRG+C

L+H

MS

Dry matter (g kg-1)

211.0

134.2

177.0

Crude protein (g (kg DM-1))

172.5

137.9

164.9

Neutral detergent fibre (g (kg DM-1))

509.0

347.0

443.0

Water soluble carbohydrates (g (kg DM-1))

186.8

141.4

118.3

Ash (g (kg DM-1))

83.0

117.0

99.0

Conclusion 

Although no prolonged periods of dry weather were observed in the 2024 grazing season, this project demonstrated that under abnormally wet conditions the L+H and the MS leys produced significantly more forage biomass in comparison to the perennial ryegrass and clover control. This project will continue in the 2025 grazing season to see if similar effects are observed should prolonged periods of dry weather occur.