Crimson clover (Trifolium incarnatum)

Datasheet

Description

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Crimson clover (Trifolium incarnatum), field, Oregon, USA

Crimson clover (Trifolium incarnatum), habit, Tarerach, France

Crimson clover (Trifolium incarnatum), flower

Crimson clover (Trifolium incarnatum), inflorescence

Common names

Crimson clover, Italian clover, scarlet clover, carnation clover [English]; trèfle farouche, trèfle incarnat, trèfle du Roussillon [French]; trevo encarnado, trevo vermelho [Portuguese]; trébol encarnado, trebol escarlata, trebol italiano [Spanish]; Inkarnaatklaver [Dutch]; Inkarnatklee [German]; Kırmızı üçgül [Turkish];نفل محمر [Arabic]; 绛三叶 [Chinese]; ベニバナツメクサ [Japanese]; Клевер пунцовый [Russian]

Species

Trifolium incarnatum L. [Fabaceae]

Synonyms

Trifolium incarnatum subsp. molinerii (Balb. ex Hornem.) Syme, Trifolium molinerii Balb. ex Hornem., Trifolium stellatum subvar. stramineum (C. Presl) Gibelli & Belli, Trifolium stellatum var. elatius Gibelli & Belli, Trifolium stramineum C. Presl

Related feed(s)

Description

Crimson clover (Trifolium incarnatum L.) is an upright annual legume growing to a height of 1 m. Crimson clover has a central taproot and many fibrous lateral roots. The stems are erect or semi-erect, and densely hairy. The leaves are trifoliate with broad and cordate leaflets, about 2.5 cm long and rounded at the tip with no white v-shaped mark on the leaflet, unlike those of the red clover (Trifolium pratense). The flower heads are conical, 2 to 6 cm in length and bear 75-125 florets each. The fruits are tiny one-seeded pods (250,000 seeds/kg). The plant dies once the seeds are mature (FAO, 2014; Young-Mathews, 2013).

Crimson clover is used as fodder and provides good quality pasture, hay and silage. It is one of the earliest forage legumes available in spring and has low or no bloat effect on ruminants. Trifolium incarnatum has many non-forage uses: cover crop; as green manure to suppress weeds; honey source; wildlife habitat; and enhancement of the landscape (Young-Mathews, 2013).

Distribution

Crimson clover originated from South-Eastern Europe and South-Western Asia Minor and now grows worldwide. It was introduced in the early 19^th century in the USA, where it is now one of the most planted annual forage legumes (Ball et al., 2000).

Crimson clover naturally occurs from sea level up to 2000 m in temperate areas. It is found along roadsides and dumps. It is a very versatile species that can be grown as a summer annual in cool climates and as a winter annual in warmer areas. It does well in most soils, including slightly acid ones provided that they are well-drained, but it is not tolerant of alkaline soils. It does not tolerate drought and has only a moderate tolerance of shaded conditions. Trifolium incarnatum regrows quickly after winter and provides an early grazing opportunity during spring (Young-Mathews, 2013).

Processes

Hay

Crimson clover has a high water content and is difficult to dry for hay (GNIS, 2014; Westgate, 1914). The harvest date should be carefully chosen: a cut too early will contain too much water and will be difficult to dry, while cutting at a later stage, after the lower flowers are faded, is not recommended, as the barbed hairs on the heads and stems become hard and wiry, and may injure the animals eating them (Ball et al., 2000). Crimson clover should be cut once dew has dried and it should be wilted before being windrowed and stored. Wilting will reduce leaf drop and subsequent loss of nutritive value (Westgate, 1914).

Silage

The high moisture and water soluble carbohydrate content of crimson clover makes it suitable for ensiling. Once dry matter reaches 30-40%, crimson clover should be finely chopped and stored in a hermetically closed silo (GNIS, 2014). Mixtures of crimson clover and grasses (such as ryegrass) are suited to baled silage as this technique prevents leaf losses. In that case, the dry matter content should be 40-50%, slightly higher than for regular silage (Andrae, 2005). For optimal silage quality, crimson clover should not be cut too short in order to avoid soil contamination and the subsequent development of butyric acid bacteria (Arvalis, 2011).

Forage management

Yields

Crimson clover in pure stands yields 2.1 to 5.0 t DM/ha (Albayrak et al., 2013; Ross et al., 2009; Gilbert et al., 1992), which is much lower than for red clover (up to 19 t DM/ha in the USA). Under Mediterranean conditions, crimson clover sown in a mixture with Italian ryegrass yielded 4.7 t DM/ha in rain-fed stands and 6.3 t DM/ha under irrigation (Martiniello, 1999).

Establishment

Crimson clover is a versatile fast-growing legume. It establishes from spring or summer seedlings. It can be sown (drilled or broadcast) alone or in combination with small grain crops or grass on a well-prepared seedbed, no deeper than 0.6 cm in clayey soils and 1.5 cm in sandy ones. Trifolium incarnatum can be mixed with other forage legumes such as vetches (Lathyrus spp), subterranean clover (Trifolium subterraneum), red clover (Trifolium pratense) and black medic (Medicago lupulina). Crimson clover can be sown with oats (Avena sativa), rye (Secale cereale), and annual ryegrass (Lolium perenne ssp. multiflorum) (Young-Mathews, 2013).

Crimson clover can be used either as a winter or a summer annual.

Winter annual

When it is intended as a winter annual, crimson clover is sown in late summer, at least 6 weeks before the first frost. It grows until frost occurs, provides fodder in November and resumes growth immediately after winter (February-March). It provides good soil cover during winter, good weed control and an early grazing fodder to livestock in early spring. In Western France, crimson clover is available a month earlier than red clover and 6 weeks earlier than alfalfa (GNIS, 2014; SARE, 2008; Ball et al., 2000). As a winter annual, crimson clover can be sown in association with a winter annual grass. The grass should be cut or grazed to prevent it from shading out crimson clover. Winter crimson clover can provide valuable green manure and is suitable for rotations: it can be first harvested or grazed by livestock and then ploughed in the soil to provide N to the subsequent summer crop (maize, wheat, cotton, etc.) (Young-Mathews, 2013).

Summer annual

Crimson clover as a summer annual is sown in May or June. It can be sown alone, once the risk of frost is over, to be harvested for hay in autumn (Young-Mathews, 2013). Crimson clover can be overseeded into a warm season perennial grass which should be removed by grazing, burning, or mowing prior to planting the clover (Ball et al., 2000).

Grazing and cutting

Crimson clover can be grazed or cut, but grazing or cutting should not start before the plants are 10-15 cm high and should leave at least an 8 cm high stubble. Trifolium incarnatum does not withstand overgrazing, though a constant grazing pressure at a moderate stocking rate may be beneficial to the plant as it limits fungal diseases (MSUcares, 2014). Though there is a low risk of bloat with crimson clover, hungry animals should not enter the stand and it is recommended to provide dry hay during periods of lush growth (Ball et al., 2000). Livestock can graze crimson clover until the blooming stage is reached. They must then be removed from the stand to allow reseeding. Once mature seeds have been dropped, livestock can re-enter the stand. Another possibility is to let crimson clover regrow and cut it for hay in summer. The stands can be grazed late in autumn and winter at moderate stocking rates (MSUcares, 2014).

Environmental impact

Cover crop

Crimson clover is a valuable cover crop. When sown during summer, its vigorous growth during the subsequent autumn provides good cover before winter and prevents soil erosion. It has a suppressive effect on weeds. Crimson clover is an N scavenger during growth, resulting in lower N losses from the soil during winter. As an N-fixing legume, crimson clover has a positive effect on the soil N status that benefits the following crop. With its dense root system, the cover crop improves soil structure and returns a good amount of organic matter.

In the USA, crimson clover blooms were found to contain minute pirate bugs (Anthocoridae), a beneficial insect that preys on pests, especially thrips. In Georgia, the use of crimson clover reduced insecticide use by 30 per cent in cotton crop (SARE, 2008).

Nutritional aspects

Nutritional attributes

Crimson clover is a high-quality forage characterized by a high protein concentration at the leafy growth stage (16 to 24% DM) (Pereira-Crespo et al., 2012; Luginbuhl, 2006; Lloveras et al., 2001). Quality declines rapidly with maturity (9 to 13% protein in the DM) (Cabiddu et al., 2010; Lloveras et al., 2001; Hafley et al., 1987). Crimson clover is a good source of phosphorus, calcium, and magnesium (Luginbuhl, 2006). Crimson clover hay has a good nutritive value (protein 17% DM, NDF 39% DM (Kiraz, 2011)).

Potential constraints

Hairs

Faded flower heads and their stems have hard hairs that may injure the animals eating them (Ball et al., 2000).

Secondary metabolites

Like other clover species, crimson clover contains tannins, isoflavones and other secondary metabolites, which may have positive or negative effects on animal nutrition and production (Oleszek et al., 2007; Cabiddu et al., 2010).

Ruminants

Crimson clover is a useful fodder for ruminants (Duke, 1981; Blount et al., 2013). It provides good grazing in autumn and early spring. It rarely causes bloat, unlike other legumes such as alfalfa or red clover (Duke, 1981).

Pasture

Crimson clover can be grazed by domestic and wild ruminants, such as the white-tailed deer (Odocoileus virginianus) (Johnson et al., 1992; Duke, 1981). It is very palatable to ruminants as both leaves and stems are readily consumed (Duke, 1981; Blount et al., 2013). In two studies comparing the grazing preference of goats for different clovers in the Southern USA, crimson clover was the most preferred clover (Terrill et al., 2004). In a mixed stand (Phalaris tuberosa/crimson clover/ miscellaneous) grazed by lactating ewes, crimson clover represented 8% of the herbage DM on offer but 33% of dietary DM. The association with crimson clover resulted in a higher DM intake but lower protein intake, probably due to the stage of maturity of the crimson clover (Molle et al., 2008). In vitro OM digestibility was high until the bud stage, varying from 83 to 77%, but it quickly declined to 50-66% after flowering (Pereira-Crespo et al., 2012; Luginbuhl, 2006; Lloveras et al., 2001). This decrease was partly explained by the presence of indigestible hairs on the surface of leaves and stems that may have lowered the digestibility (Akin et al., 1982).

Crimson clover is often grazed in a mixture with small grain cereals or various grasses such as ryegrass or bulbous canary grass (Phalaris tuberosa) (Marian et al., 2009; Molle et al., 2008; Luginbuhl, 2006). It may be used in mixtures with warm-season perennial grass pastures such as Bermuda grass (Cynodon dactylon) or Bahia grass (Paspalum notatum) (FAO, 2014; Blount et al., 2013). In Southern France, crimson clover mixed with bulbous canary grass resulted in an average daily gain of 50 g/d in lactating Roussillon and Lacaune ewes (Molle et al., 2008). In the USA, heifers grazing annual ryegrass overseeded with crimson clover had an average daily gain of 1.2 kg/d (Briggs et al., 2012). Captive white-tailed deer bucks that were fed on crimson clover during 2 consecutive winters gained 17.7 kg and 3 kg BW respectively (Johnson et al., 1992).

Hay and silage

Crimson clover hay has a good nutritive value provided it is not cut too late, as the hard hairs of the mature plant may be deleterious to livestock (Kiraz, 2011). Crimson clover makes good silage as it is rich in soluble carbohydrates (Pereira-Crespo et al., 2012; Cabiddu et al., 2010).

Horses and donkeys

In the Southern USA, in a comparison of the forage acceptability to horses of several grasses and clovers, crimson clover, berseem and subterranean clovers were found to be highly palatable (McCann et al., 1991).

Nutritional tables

Tables of chemical composition and nutritional value

Crimson clover (Trifolium incarnatum), aerial part, fresh

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used