Red clover seed can produce a high-quality, cost-effective source of homegrown protein, with the capacity to reduce the reliance on bought-in feed. It has the potential to fix 150-200 kg N/ha, releasing it to other plants and reducing the need for nitrogen fertiliser.
A short-lived perennial herbage legume, red clover typically persists for three to four years. It is very different to white clover with an upright growth habit and a strong deep tap root.
It grows from the crown at the base of the stem, where it stores nutrients for the plant. Avoiding damage to the crown is important to ensure crop persistency.
Red clover seed can be grown as a monoculture but is more commonly sown with perennial or hybrid ryegrass to produce high yields of protein-rich forage for conservation.
Benefits of sowing red Clover seed
- The primary benefit of clover is the ability to capture or ‘fix’ nitrogen from the air and feed it into the soil and surrounding plants. Red clover can supply 150-200kg N/ha reducing the requirement for artificial nitrogen
- When sown in conjunction with perennial ryegrass, yields of 12-15t DM/ha are achievable from swards with a high clover content
- Red clover swards are very palatable under grazing and when conserved leading to higher intakes and increased liveweight gains or milk and protein yields
- Red clover’s superior feed value from its high protein (16-20%) and mineral content produces excellent animal performance with a reduced need for bought-in feed
- The protein in red clover is particularly high and due to a form of biochemical protection, protein loss in the silo is reduced. Its feed value is greater than it appears on analysis due to the protein composition, and exceptional finishing results can be achieved
- The high mineral content, especially magnesium, reduces the risk of diseases and disorders linked to mineral deficiencies
- Growing red clover can improve soil structure and builds soil fertility in mixed cropping and organic farm systems. As well as being a suitable break crop, red clover can also be used as a green manure crop.
Understanding red clover
Red clover grows from the crown located above the ground. Careful management is required to avoid damaging this part of the plant and to protect the crop’s longevity. Its strong, deep taproot acts as a nutrient pump, making it more suitable for deep, fertile soils.
The finer roots have nodules containing Rhizobia bacteria. These bacteria have a mutually beneficial (symbiotic) relationship with the plant. Clover provides food and shelter for the bacteria, which in turn convert atmospheric N to usable nitrate in the soil.
Red clover has little winter growth but tolerates the winter cold and has good drought resistance. It is generally expected to have a lifespan of three to four years in the sward, depending on management.
However, scientists in Germinal’s research and innovation team, Germinal Horizon, have bred a new generation of long-term red clovers dramatically extending the life of red clover swards.
Modern varieties such as AberClaret are also more tolerant of grazing making them suitable for use in rotational grazing systems.
AberClaret can persist for four to five years under cutting, producing over 14.6 t DM/ha in year four. It is also significantly more tolerant of grazing by dairy cattle.
Advice for sowing red clover seed
Red clover is best sown as part of a full reseed from April to late July in well-drained, fertile soils. It is most often sown as a mixture with ryegrass. Oversowing is not recommended.
- Soil test. Target a pH of 6.0-6.5 and Index 3 for P & K
- Spray off the old sward with glyphosate
- Apply lime as required to correct soil pH
- Create a fine, firm seedbed to ensure good soil-to-seed contact
- Sow seeds no deeper than 10mm, to ensure seedlings have sufficient energy to emerge
- Apply P and K in line with soil test results; fertiliser N is generally not necessary
- Apply a clover-safe weed spray approximately 5-6 weeks after establishment
- A light conservation cut can be taken in the first sowing year depending on the sowing date
- Graze swards lightly in the autumn of the sowing year. Avoid grazing in wet weather when the crown of the plant is more susceptible to damage
- Ensure a five-year break between red clover crops to reduce the risk of soil-borne pests and diseases and extend to seven years if clover rot or stem eelworm is known to be present.
Stem eelworm is the major pest of red clover, first seen as patches of crop with poor growth and stunted plants. Clover rot (Sclerotinia) is the most serious disease affecting red clover, typically seen in the winter.
The clover leaves become peppered with brown spots and generalised rot of the crown, leaves and stems. Pests and diseases can also be spread between fields by infected plant material or soil on machinery.
Red clover silage management
Intermediate or late heading perennial ryegrasses are ideal companion grasses for conventionally cut red clover mixtures. As red clover is relatively low in water-soluble carbohydrates, using grasses with a high water-soluble carbohydrate content increases the energy levels overall and improves the ensiling process.
- For optimum quality, cut three to four times per year (at 6 to 8-week intervals) to a height of 7-8 cm
- Leaf is prone to shatter so disengage the mower conditioner and avoid excessive handling of the mown crop
- Red clover is low in dry matter (DM) so a good wilt is essential. Wilt for up to 48 hours, aiming to ensile at 25-30% DM
- Artificial N is unnecessary. It is important to apply adequate P and K to maintain soil at an index 3 and allow for offtakes of the crop. A 15-tonne crop requires 375 kg potassium (K) per hectare (300 units/acre)
Red clover is an excellent form of aftermath grazing for sheep. Lamb growth rates are particularly good from red clover compared with ryegrass. Red clover can also be combined very effectively with white clover, Puna II perennial chicory and Tonic plantain for an outstanding lamb finishing mixture.
- A light grazing in the autumn is acceptable
- Introduce slowly and once introduced retain as a consistent component of the diet, avoiding daily fluctuations in the quality and quantity offered
- To reduce the risk of bloat, avoid grazing with hungry stock or in wet conditions. Never allow stock to gorge themselves on clover-rich pastures and move stock onto dry rather than wet pasture
- Feed roughage, such as straw or hay, before turning out and, if necessary, during grazing
- Affected animals can be treated with anti-foaming agents or, in severe cases, remove animals from clover swards and seek veterinary advice
- The risk of bloat from red clover silage is negligible
- Red clover can contain up to 1% of oestrogenic compounds. Avoid grazing with breeding ewes and rams six weeks either side of breeding as the phytoestrogen content of red clover can reduce conception rate
- Store lambs can be offered red clover swards and silage at any time and reports of red clover affecting cattle fertility are rare
- Minimise poaching as it reduces crop persistency
Germinal red clover silage mixtures
Red Clover Intensive Silage
An intensive, three to four cut red clover silage mixture designed to produce high-quality silage with little or no nitrogen fertiliser required.
|4.00||AberClyde||Perennial ryegrass (T)|
|4.00||Red clover blend|
Organic Red Clover Silage Mix (73% Organic)
A red clover silage mixture containing 73% intermediate organic perennial ryegrasses and 27% red clover seed. Before sowing this mixture, organic farmers will have to apply for derogation.
Germinal Horizon research and innovation
Part of Germinal’s research and innovation team, Germinal Horizon, is based at the world-renowned Institute of Biological, Environmental and Rural Sciences (IBERS) in Aberystwyth. The main objectives of the team’s current red clover breeding programme are:
1. Maximising yield and increasing persistency, maintaining yields into the fourth year and beyond
Long term trial plots are showing fourth-year data for new varieties producing up to 14 t DM/ha. Over the four years, the new material is totalling around 60 t DM/ha compared with 40-45 t DM/ha from the controls.
2. Greater resistance to pests and diseases, particularly of Sclerotinia and eelworm
Several breeding lines with improved resistance have been identified and these, along with resistant wild ecotypes collected from around Europe and Asia, are being used to develop new varieties of red clover.
3. Improved nutritional quality to enhance protein utilisation and reduce nitrogenous losses
Nitrate pollution is a longstanding issue of water quality and there is awareness of the need to improve efficient utilisation and retention of plant-available forms of nitrogen.
This includes improving nitrogen uptake from the soil (reduced leaching) and reducing nitrogen losses in the silo (increased retention through increased PPO activity).
4. Enhanced polyphenol oxidase (PPO) levels to prevent rapid degradation of plant proteins and lipids in rumen and in red clover silage
A proportion of the protein content of red clover is lost through oxidation under silage. In suboptimal conditions, this can be as high as 30% of the overall content, with the nitrogen content of the degraded protein being lost through leaching. Similarly, a large proportion of plant proteins are degraded in the rumen, resulting in its loss before digestion by the grazing animal.
The enzyme PPO plays a role in protecting protein from this degradation. Enhancing PPO levels helps the retention of protein through silage and digestion, maximising the nutritional qualities of the forage and preventing loss of nitrogen to the environment. PPO also protects plant membrane lipids during silage and in the rumen, improving the fatty acid profile of milk produced by cows fed red clover by increasing polyunsaturated fatty acids and decreasing saturated fats.
5. Improving tolerance of grazing and trampling by selecting for strong crowns to allow greater flexibility in use (eg. aftermath grazing)
6. Improved winter survival
7. Extension of growing season through earlier spring growth
8. Greater tolerance of environmental stresses, particularly drought
For more details on red clover seed, silage or management, please contact a Germinal expert.