Cilywinllan Project update - Final

Key results:

• If the longevity of the leys is taken into account, direct drilling offers a cost saving of £24.71/ha in comparison to ploughing.

• More sown species were present in the ploughed plot compared to the direct drilled plots during the first grazing season.

• There was no difference between the change in soil structure or herbage biomass between the establishment methods.

• Mycorrhizal fungi had a positive effect on total earthworm numbers across all plots.

Background:

Eifion Pughe and Menna Williams contract rear dairy heifers on 61 ha at Cilywinllan near Machynlleth. Making the best use of home-grown feed is critical to cost control in the business and, ultimately, profitability. Deep-rooting herbal leys have been key to maintaining grazing when hot and dry summers have challenged grassland and, as the business seeks to expand its acreage of legumes and herbs, it has been trialling a range of establishment methods in conjunction with Farming Connect to identify which are the most efficient and effective.

Purpose of the work:

The project aims to identify the most efficient and effective way of reseeding a mixed ley and will compare three establishment methods for a mixed ley seed mixture:

1. Comparing the success rate of the mixed ley establishment based on botanical composition of each subplot at two points during and after the first grazing season
2. Determine the effect of applying Mycorrhizal fungi and rhizobacteria at the recommended rate to the seed mixtures when sowing
3. Compare earthworm populations across all plots to determine the effect each establishment method has on earthworm activity and therefore soil biology and health.

What we did:

Three loamy soil and west facing fields (2.2 - 2.7 ha) once managed as one were split vertically into two to create 6 sub-plots. The fields have not been reseeded in over 30 years and were all soil sampled and deficiencies in soil nutrients rectified at the start of the project. The different treatments are listed in Figure 1.

Figure 1. The treatments applied across the 6 sub-plots

For the crop establishment (August - September 2023) the following actions were undertaken:

1. Plough and work subplots 2a and 2b from 30 August
2. Destroy current pastures in subplots 3a and 3b using Glyphosate at recommended rate on 7 September
3. Destroy current pastures in subplots 1a and 1b using Glyphosate and recommended rates of Fulvic acid and Citric acid on 4 September
4. Apply Calciprill at a rate of 200 kg/ac (494.21 kg/ha) to all plots on 9 September
5. Apply fertiliser for establishment at 100 kg/ac (247.11 kg/ha) of 05:24:24 on 9 September
6. Direct drill seed at recommended seed rate for plots 1 and 3 using Vredo drill on 9 September
7. Broadcast seed at recommended seed rate for plot 2 on 9 September
8. Consolidate with grassland roller to ensure good soil to seed contact on 9 September
9. All plots were lightly grazed by sheep in late November to encourage tillering before being registered for the winter
10. Due to poor weather over the winter and early spring 2024, plots were managed with on-off grazing ensuring stock were not grazing for more than 4 days in the same paddock followed by a sufficient rest period.

The following data was collected to monitor the trial:

• Senus Terrain app was use to record the botanical composition, visual evaluation of soil structure (VESS) and earthworm counts in the plots before and at the end of the 2025 grazing season

• Herbage biomass availability was measured monthly (July - October 2024) via cut & weigh.

Due to poor weather over the winter and early spring 2024, growth rates were slow and the grazing and monitoring were delayed.

Outcomes:

Establishment cost

Due to the higher cultivation costs, ploughing was the most expensive establishment method, Table 1. If the longevity of the leys (3-4 years) is taken into account, direct drilling offers a cost saving of £24.71/ha in comparison to ploughing.

Table 1. Cost of establishment per plot vs Farm Advisory Service (FAS) figures.

Botanical composition

●      Pre-grazing February 2024 - 73% of the sown species were consistently present across the ploughed plots (2a and 2b) compared to an average of 32% of the sown species being consistently present within the direct drilled plots.

●       Post-grazing November 2024 - the same pattern was seen with the ploughed plots (2a and 2b) still having the most sown species present at an average of 60% compared to an average of 22.5% in the direct drilled plots.

Figure 2. Percentage of sown species present in the pre and post-grazing assessment for the six plots.

Biomass availability

• There was no difference between total herbage biomass measured between each establishment method or inclusion or exclusion of Mycorrhizal fungi.

Soil structure

• There was no difference between the change in VESS scores between the establishment method treatments.
• Post-grazing October 2024 - whilst still scored as ‘Good’, all of the VESS scores were poorer than the pre-grazing scores, possibly due to wet conditions during the grazing season leading to soil compaction from livestock trampling.

Earthworm counts

• The inclusion of the Mycorrhizal fungi increased earthworm counts and could have a long-term benefit through increased soil biological activity.

Farmer feedback: Eifion confirmed that there was a stark difference in the number of sown species present in the ploughed plots which led to Plot 2 being grazed more often that Plot 1 and 3 during the 2024 grazing season.

How to apply on your farm:

1. Test and assess soil conditions before deciding on the establishment method. Also consider timing and weather forecast. Correct pH and nutrient status in advance - pH of around 6.3, with P and K indexes at 2.
2. Ensure effective weed control pre-establishment.
3. Use the Multi-Species swards seed mix calculator to plan seed mixture to match what is required of the ley.
4. Mycorrhizal fungi product - If considering using a product containing MF, read about how they can benefit a multi-species ley and consider factors such as past cropping and establishment method before deciding whether to use. Performing a Phospholipid Fatty Acid (PLFA) soil test is an option to give a snapshot of soil biology.
5. Ensure you are ready and equipped to manage the leys in a way that will ensure the forbes and legumes persist as long as possible in the sward to ensure maximum ROI.

Image: Plot 2 on August 2024 

Please contact timtechnegolcff@menterabusnes.co.uk if you would like to receive a copy of the full final report for this project.