Update from the Clover150 Programme

In 2021, a group of 30 farmers from across the country enrolled in the Clover150 programme, with a range of land types, geographic spread and farming enterprises. Over the past two years, white clover was established on farms by a combination of reseeding and oversowing.

The objectives of the project were:

1. Maintain herbage production ≥ 14 t DM/ha grown;
2. Reduce nitrogen (N) Surplus 40%;
3. Reduce N fertiliser to ≤ 150 kg N/ha per year;
4. Achieve an average sward clover content of 20–25%;

Results to date

The area of the farms in clover at the end of 2022 was 64%, with an average sward white clover content of 18% - an increase of 6% from 2021. Sward clover content between reseeded paddocks and oversown paddocks was similar at 19% and 18%, respectively. The improved establishment of white clover has resulted in a 48kg N/ha reduction in whole farm chemical N input from 206kg N/ha in 2021 to 158kg N/ha in 2022. This in turn has led to a significant improvement in the whole farm gate N surplus from 179kg N/ha in 2021 to 139kg N/ha in 2022. This will have a significant impact within farm systems, with potentially less available N to be lost to the environment. Grass grown on farm, however, has reduced by 1t DM/ha, with a large proportion of this reduction caused by the drought in late summer in 2022. Over the next number of years, as the clover area and clover content increases on the farms, there is even greater potential to reduce chemical N applied on farm and lead to reduced N surplus, while maintaining feed self-sufficiency on farm.

Key recommendation from the Clover150 programme

Clover will be the main innovation responsible for a rapid reduction of chemical N on farm as shown on Clover 150 farms. Below are recommendations developed form the project:

• Identify and tailor N application for individual paddocks:
• Carry out a N plan for 2023 on PastureBase Ireland.

• Greater use of soiled water in summer:
• ~2,500 gallons of slurry / soiled water per rotation can successfully replace chemical N in summer rotations on established clover swards (> 25% clover).

• Continue to increase clover area and content:
• Over sow approximately 15% of farm in late March/April;
• Reseed 5-10% per year.

• Maintain balance of grass and clover – average 20-25% annually:
• 10-15% in spring;
• 20-25% in summer;
• < 40% in autumn.

Table 1: Herbage production and nitrogen application on the Clover150 farms for 2021 and 2022