Principles of organic production

Organic production requires a planned approach. Each individual holding develops its own integrated system based on its own particular circumstances such as soil characteristics, pasture and crop needs, livestock and housing. This information is based on EU organic standards, but independent standards may contain modified or additional requirements.


The basis of organic production is a healthy, biologically active soil, with good organic matter reserves, that can supply nutrients for the production of grass, crops and vegetables.

This involves providing the soil with materials that can be broken down by soil microorganisms to release crop nutrients.

In practice this involves developing cropping, grazing and silage rotations that do not over-exploit soil nutrient reserves, plus managed use of manures, thus maintaining soil fertility.

Sustainability and self-sufficiency

Organic production is not simply low-input production, nor is it a return to old-fashioned production.

Organic production is a combination of :

  • top quality husbandry and management
  • using modern machinery and appropriate modern technology
  • dedication and skill

A productive organic farm will develop a system that is largely self-sufficient in many of the inputs that are often bought in on conventional (non-organic) farms.

This makes sense in terms of developing a sustainable system, but in many cases such inputs are not readily available in organic form, or are very expensive.

Crop nutrients

A balanced cropping rotation incorporating legumes is the basis for nutrient provision. This is then supplemented by organic materials including, in general terms:

  • farm yard and poultry manures
  • composted plant materials and crop residues
  • green manure crops

It may be possible to seek approval to utilise limited quantities of manure from a conventional farm, providing it is not from an intensive system, and proof that the animals that produced the manure have not been fed any GMO feed.

All manures should be properly composted.

Additional materials that may be used (prior permission may be required) include :

  • rock minerals and liming materials
  • a range of processed organic wastes and by-products (GMO free)
  • seaweed and seaweed products

Importance of legumes

The key to a successful rotation is the correct incorporation of legumes in the rotation. This principle is true for livestock, arable and vegetable production holdings.

The reason is quite simple; legumes, in association with specific soil bacteria, are able to take atmospheric nitrogen and convert it to nitrogen fertiliser.

In short, legumes are the main source of nitrogen on the farm.


Although all-grass farming systems can be operated, organic farms should ideally have a practical, balanced cropping rotation incorporating one or more of the following :

  • grass/clover leys
  • arable crops and/or vegetables

The main functions of rotations are :

  • maintaining soil fertility and supplying crop nutrients
  • supplying animal fodder and feedstuffs, and clean grazing
  • providing weed, pest and disease breaks

Green manures (cover crops)

Although green manuring is not a common technique with conventional (non-organic) producers in the UK, it has been widely adopted by organic producers, particularly market gardeners.

Green manures are crops grown, usually without a saleable value, in order to :

  • provide organic matter and available nutrients
  • provide nitrogen (legumes)
  • protect the soil surface and prevent leaching of nutrients over winter – for example, forage rye
  • smother weeds
  • provide weed, pest and disease breaks
  • provide compostable or mulching materials

They are included in rotations to fulfill one or more of these functions and, depending on the type used, they can be grown for a few weeks, up to a full year.

In vegetable holdings green manures are an essential part of the rotation since they may be the major source of available nutrients, particularly nitrogen, and organic matter. This is especially the case when acceptable manures and composts are in short supply or unavailable.

Weed, pest and disease control

There are no herbicides, and very few pesticides, available to organic producers. Alternative means of controlling weeds, pests and diseases are normally utilised.

The starting point is a sound rotation.

Basis of weed control

Weed control is often the main concern amongst new organic producers. Weed control techniques include :

  • sound rotations
  • mechanical cultivations and specialised equipment
  • flame / heat weeding
  • grazing and topping
  • stale seedbed techniques
  • cover crops and mulches

Basis of pest control

Pest control techniques include :

  • correct rotations and resistant varieties
  • encouraging pest predators
  • physical barriers (for example, fleece covers)
  • biological control agents
  • permitted pesticides (prior permission required)

Basis of disease control

Disease control techniques include :

  • correct rotations and resistant varieties
  • biological diversity
  • good field hygiene
  • permitted fungicides (prior permission required)

Organic crop production

Organic crop production can be an integral part of the cropping rotation. This may be in order to provide animal feed or as a cash crop.

Cropping utilises soil nutrients and, apart from crop residues, does not add to soil fertility.

Cropping should normally occupy less than 50 percent of the rotation and should ideally be spread over the rotation cycle, allowing periods of fertility building.

Organic livestock production

Organic livestock production is extensive, involving modest stocking rates, irrespective of the type of stock involved, including poultry.

Livestock must have access to grazing when ground conditions permit.
In general terms, organic standards prefer that, as far as possible, closed herds/flocks are maintained. This is an important element in reducing the risk of new disease coming into the farm. This will involve breeding policies that promote sustainability, aligned with carefully controlled culling and stock replacement.

Ideally, stock coming onto an organic farm should be sourced from other organic farms. Limits are put on the number of conventional replacement stock allowed each year. Non-organic stock can never themselves later be sold as organic.

Livestock feed

Feed should be from organic or inconversion sources, largely produced on the farm itself.

Purchased organic livestock feed is expensive and can be difficult to obtain. It must be obtained from approved sources.

Feed production should ideally centre around developing a crop rotation that produces the feed requirements for the farm, with only materials that cannot be produced on the farm being purchased.

Animal welfare

A very high degree of animal welfare is built into organic standards in line with consumer expectations.

Stock must be provided with a comfortable, dry bedded laying area. Loose housing which is well bedded is preferred. Fully slatted houses are not permitted (50 percent maximum slats is allowed for drainage).

Organic standards specify generous space requirements for housed animals and birds.


The maintenance of good health through sound animal husbandry is a fundamental requirement in organic livestock production.

A detailed animal health plan must be drawn up at the start of conversion, and it must be updated and maintained as the conversion and subsequent organic production progress.

Full records of all treatments must be maintained.

Most medication is allowed where a real need can be demonstrated, and there are very few veterinary medicines which are not allowed in organic production.

Routine prophylactic (preventative) administration of medicines to all animals in a herd or flock is not normally allowed. Animals must be treated on an individual basis.

Vaccination is permitted under derogation in cases where there is a known disease risk.

Withdrawal periods are usually at least twice the legal withdrawal period, and at least 48 hours.

Vegetable production

Organic vegetable production can be an integral part of a farm rotation or can be based on a specialised vegetable unit.

Special attention is required in developing rotations for vegetable production in order to maintain the necessary soil fertility and prevent the build up of pests and diseases.

Organic seeds and plants

Vegetable seed, transplants and vegetatively propagated materials such as fruit bushes and trees, seed potatoes, onion setts and strawberry runners must normally be obtained from a registered organic source.

Derogations for the planting of untreated, nonorganic material can sometimes be obtained when suitable organic material is not available. Prior permission must be sought from your control body, and sound reasons must be presented.

Environmental conservation

Organic standards pay high regard to cross-compliance, protection and enhancement of the environment including :

  • prevention of pollution
  • proper management of trees and hedges
  • provision and maintenance of wildlife habitats and species-rich grassland and wetlands
  • retention of traditional walls and gates, buildings, monuments and landscape features.

White clover

Benefits of grass/clover swards compared to grass swards

  • can produce similar dry matter yield as a grass sward receiving 200 KG of fertiliser nitrogen per hectare (6 bags of 27 percent nitrogen per acre)
  • maintains high digestibility over longer period leading to improved intakes
  • up to 10 percent higher liveweight gain in cattle, 20 percent more milk from dairy cows and 25 percent higher liveweight gain in sheep
  • enhances lean meat gain and milk protein content
  • contains more minerals, in particular magnesium, thereby reducing the risk of animal health problems associated with mineral deficiency
  • saves on energy usage thereby indirectly reducing environmental pollution
  • evidence of reduced nitrogen loss to the environment
  • greater biodiversity

Clover is the key to organic grassland management

The provision of good levels of herbage production on organic farms depends on achieving high clover contents in swards.

The ability of clover to capture nitrogen from the air is well known but the potential value of clover-based swards is often underestimated.

However, maintaining the high clover contents in swards required to achieve satisfactory levels of production needs careful sward management.

Establishing clover

Choice of clover varieties

White clovers are classified according to leaf size:- small, medium, large and very large.

Small leaved varieties survive best under intensive sheep grazing as they have a creeping growth habit. However, they can be expensive, and some varieties can, at times, be in short supply.

Medium leaved varieties are generally tolerant of a wide range of conditions and should always be included in mixtures intended for all grazing uses.

Large leaved varieties are for general purpose use and are best suited to rotational grazing by cattle or sheep or where some silage is taken.
Very large leaved varieties are high yielding but are least persistent under grazing and are best confined to hay or silage swards with only limited grazing use.

The best compromise is to use a mixture of clover varieties, half of which should be medium leaved. The remainder should be either small, medium or large leaved varieties depending on the intended sward use.

Varieties such as Crusader, Chieftain and Barblanca grow earlier in the spring.

The table below shows the most readily available recommended varieties in Northern Ireland. 

White clover performance - small leaved
Control yield (t DM/ha) 4.3 Relative leaf size percent of Huia Clover yield potential percent of control Grazing persistence 0-9
Aberace 39 57 6.5
Crusader 84 99 5.8
Gids demand 74 84 6.3
White clover performance - medium leaved
Control yield (t DM/ha) 4.3 Relative leaf size percent of Huia Clover yield potential percent of control Grazing persistence 0-9
Glds. Bounty 87 98 5.9
Avoca 91 101 5.9
Aberdai 96 105 5.4
Chieftain 101 121 5.3
AberHerald 87 103 5.0
AberVantage 98 103 5.2
Glds Huia 94 86 5.8
White clover performance - large leaved
Control yield (t DM/ha) 4.3 Relative leaf size percent of Huia Clover yield potential percent of control Grazing persistence 0-9
Alice 118 113 5.1
Barblanca 122 119 5.6
White clover performance - very large leaved
Control yield (t DM/ha) 4.3 Relative leaf size percent of Huia Clover yield potential percent of control Grazing persistence 0-9
Aran 155 120 4.3

Note: Varieties in bold type have performed best over many trials

Choice of companion grass for clover

Intermediate heading perennial ryegrasses, particularly some tetraploid varieties, are the best companion grasses for clover. Varieties need to be selected with care.

  • select erect, less aggressive types such as Foxtrot, Spelga and Portstewart. These types develop a sward structure which will help encourage the spread of clover
  • tetraploid varieties such as Dunluce, Aberglyn, Delphin and Dunloy may assist in maintaining an open sward, which should help to promote a higher clover content
  • hybrid ryegrass varieties, which combine the characteristics of perennial and Italian ryegrasses, should encourage clover development due to their more open structure

When reseeding on heavy soils, it may be worth replacing 2-3kg/Ha of perennial ryegrass with Timothy such as Comer, Comtal or Motim.

The inclusion of herbs, such as Chicory, Ribgrass (Ribwort plantain) or Bird’s Foot Trefoil, can also be considered on organic farms. Although many herbs will germinate and grow quite readily in reseeds they can be difficult to maintain over time and add to the cost of seed mixtures. They are deep rooting and provide a rich source of minerals and tannins to grazing livestock. Herbs can alternatively be sown in areas of fields where grazing can be controlled.

When the primary use of a sward is silage rather than grazing the use of red clover with Italian and hybrid ryegrasses could be considered.

Establishing clover-rich swards

There are several ways of achieving clover-rich grass swards:

Direct reseeding before the end of August is the most reliable method of establishing grass/clover swards. To ensure a good establishment of clover, be generous with the clover seed and economise on the grass seed.

The best compromise is about 25 KG of perennial ryegrass with 4-5 KG of clover seed, sown at about 30 KG per hectare. The seedbed should be firm and fine and should be rolled prior to sowing the grass/clover mixture.

Undersowing can be useful for spring reseeds, using early maturing spring cereal varieties as the cover crop.

Overseeding methods can be used to place seed into an existing sward, such as direct drilling using the Vertikator, very light cultivation followed by sowing with an air seeder such as the Einbock, Guttler or discing ground and broadcasting the seed.

In all cases it is essential that competition is minimised by grazing the sward tightly (4-5 cm) in late July, or by following in immediately after a silage cut taken mid-July to late August, with soil conditions neither excessively wet nor dry.

Strip or slot seeding can also be used to upgrade existing swards but the technique has given variable results under local conditions.

Minimal cultivation represents an alternative to strip or slot seeding in that the technique does not involve ploughing. If discing, set the disc with minimum cut (coulters running straight) and add weight.

Disc the field in several directions to open up slits in the ground before sowing when soil conditions are dry. Roll after sowing to achieve good seed to soil contact, conserve moisture and ensure rapid germination.
Slurry seeding may be an option in circumstances where the existing sward has become thin and in need of rejuvenation.

Pasture management to encourage clover can have a significant impact provided clover is well distributed throughout the field at the outset.

Key factors in reseeding

All the basic principles for any reseeding operation must be considered as part of an overall sward improvement programme, for example, adequate drainage, pH, fertility, weed and pest control.

Soil analysis to keep a check on soil fertility is worthwhile every three to five years.

Soil samples should be taken from any fields to be reseeded. Aim to maintain a soil pH status of 6.0-6.5, using lime to correct it.

In addition to manure and slurry, some natural sources of phosphate and potash, such as ground rock phosphate and rock potash, can be used to maintain soil fertility. If applying rock phosphate, evidence of need is required under the Phosphate regulations.

For successful clover establishment, by any method, there are some principles that must be adhered to:

  • correct timing - Late summer (August) is best for seed germination and full plant development before winter
  • proper soil fertility - Soil phosphate and potash status should both be at least index 2 and soil pH should be between 6.0 and 6.5
  • good seed/soil contact - Seeds need to be placed into a firm, shallow (1-2 cm) seedbed
  • control grass competition - The existing grass sward cover must be kept low before and after seed sowing, otherwise the young seedlings will not survive

Encouraging clover in existing swards

Provided clover is well distributed throughout the field, even though it may not be contributing much to sward productivity, it may be possible to encourage the development of a productive clover rich sward without the need to reseed.

To determine the suitability of a field for rejuvenation there must be a high proportion of productive grass species present and a clover assessment should be carried out.

As you walk across a field you must see clover within 0.5 m of your foot in 8 out of every 10 inspections, preferably carried out every 20 paces over the entire area of the field.

If there is an even distribution of clover throughout the sward, adopt the management guidelines given below:

  • graze hard (3-5 cm) with sheep or light cattle during November/December
  • avoid under-grazing during spring/early summer
  • rest for three to four weeks during July or closing off for silage
  • avoid poaching
  • avoid smothering with slurry
  • avoid spreading silage effluent
  • control broad leaved weeds

Weed control

In direct sown swards, or swards undersown in an arable silage crop, topping or forage harvesting can control many weeds.

Grazing with sheep whenever the grass is 10 cm tall can provide a useful degree of control of annual weeds like chickweed, hempnettle and redshank. This can also help control ragwort in established swards.

However, care must be taken to avoid overgrazing and poaching, especially when soil conditions are wet. Periods of frost can provide an opportunity to graze with minimal damage.

Thistles do not survive long if repeatedly topped before flowering. Docks are the most difficult weed to control in an organic system and regular topping to prevent flowering is recommended.

Pest and disease control

Clover is even more susceptible to leatherjackets than grasses, although clover will eventually recover after most attacks.

Although a number of diseases can affect both white and red clover there are no routine recommendations for their control.


Bloat can occur in both beef and dairy cattle grazed on lush, clover-rich swards. However, the condition can also occur on all-grass swards.

As part of normal rumen function the large volumes of gas normally produced are belched and the animals suffer no discomfort.

However, when bloat occurs a stable froth is produced which inhibits both normal belching of the gas and rumen contractions.

Sub-clinical and clinical bloat can affect productivity, while in severe cases death can result from heart failure and from asphyxia.


  • feed roughage, such as straw or hay, before turning out and, if necessary, during grazing
  • sheep selectively graze clover and are not prone to bloat. Grazing sheep ahead of cattle reduces the risk
  • never allow hungry cattle to gorge themselves on clover-rich pasture
  • cattle moved onto dry rather than wet pasture are at less risk
  • affected animals may be treated with antifoaming agents
  • in severe cases remove animals from clover swards and seek veterinary advice

Fluctuations in production

The productivity of grass/clover swards can be more variable, both within and between seasons, when compared to grass swards dependent on artificial nitrogen fertiliser.

Clover-based swards are slow to start growing in the spring. Early growth can be encouraged through strategic use of slurry and farmyard manure. It is important that the resultant flush of grass is grazed down efficiently to allow subsequent growth and development of clover within the sward.

Target clover content

In most situations the clover content of swards is at its peak from late July to mid-August. The spring target should be 30 percent ground cover, indicating that adequate clover has survived the winter and that it will be able to compete with grasses that grow more quickly than clover in spring. Ground cover is the proportion of the ground covered with clover leaves.

By mid-June, clover ground cover should be increasing to about 40 percent. A peak of 50-60 percent clover ground cover is required by early August. This results in the best compromise between the quantity of herbage produced per hectare and the nutritional value of the herbage.

If the clover content is very high, overall yield decreases, since there is not enough grass to utilise the nitrogen fixed by clover. While the nutritional value of the available herbage rises, the risk of bloat in cattle is also increased. However, too little clover will eventually result in poor production.

The proportion of clover required to improve individual animal performance depends on the type of stock and the grazing system adopted.

For example, sheep in rotationally grazed swards can show enhanced performance with an average clover cover of 20-30 percent over the season. This is due to their ability to selectively graze clover.

In set-stocked systems sheep performance has benefited from the presence of a lower content of clover (less than 20 percent cover) over the season.
In cattle systems, swards need to contain 4055 percent average cover in order to enhance individual animal performance.

Seed Regulation

All seed sown on organic farms should be certified as organic. Organically produced seed can be in short supply, so if sufficient suitable organic seed cannot be sourced producers must request a derogation from their sector body to use untreated non-organic seed.

However, the proportion of non-organic seed allowed is reducing year by year. 

Red clover

Red clover-based swards on organic farms

Red clover silage swards can meet the forage requirements of an organic farm whilst improving the protein content and overall feeding value of the winter forage.

Red clover is better suited to silage production than white clover because of its much more erect growth habit and its significantly higher forage yields.

It will not persist if grazed more frequently than every 30 days due to a combination of excessive foliage removal and plant crown damage by hoof trampling. Typical persistence is two to three years, that is two full harvest years after the establishment year.

Red clover can also be used as a green manure crop on cropping and horticultural units. It is particularly valuable for building soil fertility once organic conversion has begun.

Benefits of red clover- based swards

  • red clover silage has a high crude protein content of 16 percent to 20 percent and a ME content of 10 to 12MJ/KG DM, depending on the growth stage at cutting
  • its better palatability compared to grass silage gives greater intakes, resulting in high levels of animal performance in terms of milk and protein yields or liveweight gain
  • swards are relatively drought tolerant due to the deep rooting ability of red clover, and are winter hardy
  • red clover is suitable as a break crop to improve soil structure and fertility, and as a supplier of organic matter
  • lambs fatten very well on red clover grass aftermaths

Forage potential of red clover

Red clover will perform best on well drained, fertile soils with a pH of 6-6.5. Typical annual requirements (based on soil phosphate (P2O5) and potash (K2O) indices of 2) for an annual yield of 12t DM/ha/year would be 100-150 KG P2O5 and 250-300 KG K2O /ha.

Normally, 80-90 percent of the annual yield is obtained from two silage cuts completed by late July - early August. Slurry or well composted farmyard manure is applied in early spring and between cuts, weather and ground conditions permitting.

Cut the crop at the early bud stage around mid-late May and again in late July, depending on rate of regrowth in mid summer. Rest the sward in September and cut or graze off herbage in October, if this can be achieved without poaching. This will encourage branching and should improve sward persistence over winter. Severe winter grazing may damage the plant crowns directly by physical damage and indirectly through soil compaction.

Late flowering varieties are more tolerant of grazing, as they produce more buds from the plant crown. Lax grazing would be beneficial to red clover in mixed swards. Sheep can apply considerable grazing pressure as they selectively graze the red clover, especially where herbage density is low.

Establishing red clover

Choice of red clover varieties

Most varieties currently available are early flowering. These have two main growth flushes during the growing season and start growth in spring earlier than late flowering varieties.

Typical persistence is two to three years, that is two full harvest years after the establishment year. Provided the overall sward management is good and sufficient nutrients can be applied, timely renovation will result in swards rich in red clover for several years.

Varieties such as Merviot, Marcom and Kuhn have good yield and Sclerotinia resistance. The more recent variety, Milvus has improved productivity and persistence.

Varieties with a stoloniferous (creeping) growth habit are being developed in New Zealand to improve the tolerance to grazing.

Choice of variety is of less importance if the red clover is being grown simply as a green manure.

Choice of companion grass for red clover

Mixtures of red clover with grass will give higher total forage yield, dry matter content, water soluble carbohydrate concentration, digestibility and metabolisable energy, than red clover dominant stands. However mixtures will have lower protein content and lower levels of some minerals such as calcium and magnesium.

Competitive, short duration ryegrasses are the best companion grasses for clover. Variety combinations need to be selected on the expected duration of the sward within the land rotation.

Red clover grown as a green manure does not need a companion grass.
Hybrid ryegrasses, bred by crossing Italian and perennial ryegrasses, make very suitable companion grasses for red clover silage swards.

Typical seed rates (kg/ha):- Red clover Grass
Red clover only 12 - 15  
Clover dominant mixture 15 5
Grass dominant mixture 7.5 22
As green manure crop 15 - 20  


  • use Italian / Hybrid ryegrasses for less than three years duration
  • use Hybrid / Perennial ryegrasses for more than three years duration

Guidelines for successful clover establishment

There are several ways of achieving red clover-rich grass swards:

  • direct reseeding
  • undersowing
  • overseeding
  • strip or slot seeding

Ensure that you:

  • test the soil and target Index 2 for phosphate, potash and pH = 6-6.5
  • sow from April to August
  • prepare a fine, firm and level seed bed
  • sow seed at 10-15 mm depth


  • young red clover plants are not very competitive against weeds
  • over the cutting season approximately 12t DM/ha (= 60 t/ha fresh) of clover/grass silage will remove 100-150KG/ha P2O5 and 250-300KG/ha K2O
  • cattle slurry @ 22m3/ha (2000 gals/ac) with 1:1 dilution, provides 10KG N, 14KG P2O5 and 54KG K2O per ha, applied in the spring

Undersowing - can be useful for spring reseeds, using early maturing spring cereal varieties as the cover crop.

Overseeding - a range of methods are available for placing seed into a sward, such as direct drilling using the Vertikator, Guttler, Einbock, power-harrowing or discing and harrowing ground and then broadcasting the seed.

Strip or slot seeding - existing swards can also be upgraded using this specialist technique, but can give variable results.

Alternatively, follow in immediately after a silage cut taken in July or August, when soil conditions are neither excessively wet nor dry.


All the basic principles for any reseeding operation must be considered, for example, adequate drainage, pH, fertility, and weed and pest control.

A routine programme of soil analysis to keep a check on soil fertility is worthwhile every three to five years.

Soil analysis should be carried out on any fields that are to be reseeded. Lime can be used to correct soil pH.

In addition to manure and slurry, some natural sources of phosphate and potash, such as ground rock phosphate and rock potash, can be used to maintain soil fertility.

Management of red clover

Weed control

In direct sown swards, topping or forage harvesting can control many annual weeds. Grazing when the grass is 10cm tall can provide a useful degree of control of annual weeds, for example, chickweed, hempnettle and redshank, and of ragwort in established swards.

However, care must be taken to avoid overgrazing and poaching, especially when soil conditions are wet. Periods of frost can provide an opportunity to graze with minimal damage.

Thistles do not survive long if repeatedly topped before flowering. Docks are the most difficult weeds to control in an organic system.

Making red clover silage

Red clover silage has a higher protein content and is often more palatable to cattle than grass silage. However, red clover is characterised by low dry matter and low water soluble carbohydrate contents and a high buffering capacity. As a result, it is more difficult to obtain a satisfactory fermentation with red clover than with all-grass silage.

It is advisable to wilt for 24-48 hours in dry conditions to achieve 25 percent dry matter content. This will also concentrate sugars to encourage a desirable fermentation and reduce silage effluent production. Overwilting can result in substantial leaf shatter and loss and it can be difficult to consolidate very dry material in the clamp.

Red clover wilted to 25 percent dry matter will often ensile effectively without an additive. However, where herbage is wet or where there is a very high proportion of red clover, an effective additive can be used to ensure a stable fermentation.

Molasses, inoculants and enzymes can be used within organic systems as silage additives.

Note that molasses used as a silage additive (or fed) must be organic itself.

When weather conditions do not allow for adequate fermentation, permission may be obtained from the organic sector bodies to use an acid additive.

Pest and disease control

A number of pests can attack clover plants, but routine control measures are not considered worthwhile.

Red clover is even more susceptible to leatherjackets than grasses, although it will eventually recover after most attacks.

Although a number of diseases can affect red clover, there are no routine recommendations for their control.

Animal problems associated with red clover

Although red clover based swards can promote better liveweight gain in cattle and sheep and greater milk production in dairy cows than grass swards, care must be taken in their utilistaion.

Breeding ewes should not be grazed on red clover, or fed red clover silage for a period of four weeks before and until four weeks after mating, to avoid any adverse effect of red clover oestrogens on lambing percentage. Lambs can be fattened very effectively on red clover silage aftermaths.
Bloat is a potential hazard when swards with a high red clover content are grazed. The risk can be reduced by feeding roughage, such as straw or hay, before turning out and if necessary during grazing.

Never allow hungry stock to gorge themselves on clover-rich pastures. Moving stock onto dry rather than wet pasture reduces the risk.

Affected animals may be treated with antifoaming agents such as proloxalene. In severe cases remove animals from clover swards and seek veterinary advice immediately.

Red clover as a green manure

Red clover grown as a green manure in a crop rotation will provide organic matter to the soil and nutrients, particularly nitrogen, for the following crop. Red clover green manures are usually put down for one to two years, often at the start of a farm conversion as a means of improving soil fertility. They have an important place in stockless arable and horticultural rotations.

Red clover green manure crops must be managed. Grazing is an option, but as animals are removed they will inevitably take nutrients with them.

Topping as a means of mulching is a second option, particularly if livestock are not available or not wanted. The sward should be topped regularly to keep it relatively short and to avoid smothering the plants with a large mass of mulched material.

Alsike clover

Alsike clover could be an option for land which is too heavy, wet or acidic to support red clover. Like red clover the plant is short lived, generally being productive for two years. However, it sets seed freely and can regenerate from shed, ripe seed if it is allowed to mature during the season. It has an upright growth habit and is usually grown in mixtures with grasses, for example, Timothy, and other forage legumes. Like red clover it does not spread and so a good distribution of seedlings is vital from the outset. The seed is small so it should be sown no deeper than 10-15mm. There is little data on production but yields of up to 10.7t DM/ha in the first year and 7.7t DM/ha in the second year are reported from Great Britain. The feeding value is similar to red clover. It too can be used as a green manure crop.

Seed regulation

All seed sown on organic farms must be certified as organic. Organically produced seed is in short supply at present, but becoming more readily available each year. In the meantime, if sufficient suitable organic seed cannot be sourced, producers must request a prior derogation from their sector body to use untreated non-organic seed. 

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