Dyfi Dairy - Summary & Key Results

The trial aimed to direct drill different herbal ley mixes for use on a Welsh upland dairy farm.

Four trial plots were established: three different herbal ley mixes direct drilled into perennial ryegrass pasture, and one pure perennial ryegrass pasture as a control.

The trial plots were designed with the following properties:

Plot 1: Cae Mawr - legume and herb rich sward: This plot was used for grazing dairy cows, with a focus on nitrogen-fixing and deep-rooting plants.

Plot 2: Cae Ffordd - meadow hay ley + diversity: This plot was used for hay/haylage, with a focus on herbs, wildflowers, and multiple grass species.

Plot 3: Cae Dan Helm - anthelmintic/goat health grazing: This plot was used for grazing goats, with a focus on plants with anthelmintic properties. 

In general, the success of the trial was hampered by weather and logistical factors. Unusually wet weather in April and May meant that the herbal ley mixes weren’t direct drilled until June. Although the pasture was topped and tightly grazed before direct drilling, the ryegrass pasture still largely outcompeted the herbal ley mixes. 

If the trial was to be repeated, ideally direct drilling of the herbal ley mixes would take place in early April. Alternatively, if the weather window for sowing ended up being later, consideration for either plough and/or harrow the fields before drilling would be taken. 

Nonetheless,the herbal ley mixes did establish in all three plots and expect to see further establishment in subsequent years (due to the seeds in the soil seed bank being disturbed by mob grazing). 

The following photos show some of the plants established in Plot 3, all of which have anthelmintic properties for goat grazing. Over the course of the trial, incidents of worm burden in the goat herd halved in comparison to previous years. 

In the short timescale of the trial (one growing season), it’s too early to see significant benefits in terms of soil health and pasture growth. However, this is something that was expected to be observed in subsequent years and there are already signs of some improvement. Organic matter improved in one plot (Plot 2) while staying roughly the same in the control plot. In the other two plots (Plots 1 and 3), pH improved while slightly declining in the control plot. 

In future trials, due to the poor pH of the soil, applying lime before sowing the herbal leys to see if that has a significant impact on their establishment may be considered. Dyfi Dairy also noted they may also consider applying a mycorrhizal inocula to improve the biology of the soil.