The inclusion of red clover in grass grown for silage helps by biologically fixing nitrogen thereby reducing the greenhouse gas emissions and costs associated with chemical fertiliser use.
Overview
Red clover is a leguminous plant with an upright growth habit and a strong deep root from which finer roots arise. Red clover is mainly suitable for silage though livestock can graze after the final silage cut and can last for over six years under good management.
Why should I include red clover in my grassland?
At inclusion rates of 25% and above the following benefits can be achieved from red clover.
- Grass-red clover can produce high yields (up to 16tDM/ha).
- Clover maintains high-quality pasture under low fertiliser input and a well-established clover sward can reduce chemical nitrogen fertiliser demand by 150- 250kg/ha annually.
- Grass-red clover swards have a high protein content(16 to 20% crude protein).
The farmer discusses grass-red clover swards.
How do I include red clover in grass swards for silage?
- Red clover grows well in moist but well-drained soils, with pH 6-6.5 and a P & K index 3.
- Applying slurry or cutting silage in wet weather should be avoided to minimise damage to the plant crowns and soil compaction by machinery.
The following video provides detailed information on the establishment of grass-red clover swards for silage.
Learn more about Red clover agronomy management
Economic and Environmental Benefits
Incorporating red clover in silage paddocks reduces the fertiliser demand by 150-250kg/ha per year. The Table below shows the potential annual savings and emission reductions when red clover is used with grass swards for silage.
Savings and reduction in emissions from red clover inclusion
| Scenario 1 Grass only | Scenario 2 Grass-red clover(10% of the area) | Scenario 3 Grass-red clover(25% of the area) | |
| Total silage area(ha) | 16 | 16 | 16 |
| The average quantity of nitrogen fertiliser (kgs/ha) | 220 | 198 | 165 |
| Fertiliser savings (€) | – | 570 | 1426 |
| Extra reseeding costs (€) | – | -213 | -532 |
| Net Savings/farm(€) | – | 357 | 894 |
| Environmental Impact | |||
| Total Emissions (kgCO2-eq /kg FPCM) | 0.960 | 0.956 | 0.948 |
| Reduction in emissions (%) | – | 0.42 | 1.25 |
The May 2023 average fertiliser prices of €520/t for CAN and €602/t for Urea were used (https://data.cso.ie/)
Net savings/ cost are the savings or cost per year for the farm
Research
Research at Farm Zero C
Red clover and perennial ryegrass (PRG) swards have been planted on some of the silage ground to reduce chemical fertiliser usage. Management practices employed to increase life span include maintenance of optimum soil pH (6.5), slurry application management, and avoiding the use of heavy machinery in wet weather to reduce damage to the red clover.
Other Research
Key findings from previous research in red clover include:
- Dry matter intake for grass-red clover swards was 1.6 kg/d higher than for grass (Johnston et al., 2020).
- The digestibility of grass-red clover swards was also higher than grass-only swards.
- Generally, grass-red clover swards have a higher protein content and digestibility than grass-only swards (Conaghan & Clavin, n.d.).
Links to more research
- Red clover overview
- Red clover in organic farming
- Red clover agronomy management
- Consider red clover for silage
Regulations
Including red clover in silage paddocks as a climate mitigation strategy is important to meet the following climate targets and regulations.
The Nitrates and water directive
The nitrates derogation– For derogation farmers, all new grass reseeds on the grassland farm shall incorporate at least 1.5 kg/ha of naked clover seed or at least 2.5 kg/ha of pelleted clover.
The Ag Climatise Roadmap 2021– The use of red clover for silage supports the following actions of the roadmap to climate-neutral agriculture.
- “Action 1: Reduce chemical nitrogen fertilizer use by 40% by 2030.”
- “Action 4: Maximise production of grazed grass.”
Available support -There is upcoming support for red clover for example the red clover silage measure by the Department of Agriculture, Food and the Marine(DAFM) to make red clover seeds financially accessible to farmers.
Suppliers
Farmers can easily purchase red clover seeds from their local merchants or cooperatives.