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Buckwheat (Fagopyrum esculentum) forage

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Datasheet

Description
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Common names 

Buckwheat, common buckwheat [English]; blé Noir, blé de Barbarie, bucail, sarrasin [French]; Gwinizh-du [Breton]; pohanka [Czech]; boekweit [Dutch]; tattari [Finland]; echter Buchweizen, blenden, Brein, gemeiner Buchweizen, Haidl, Heidenkorn, Heidensterz, schwarzes Welschkorn, türkischer Weizen [German]; Φαγόπυρον το εδώδιμον [Greek]; grano saraceno [Italiano]; gryka [Poland]; trigo mouresco, trigo sarraceno [Portuguese]; Hrișcă [Romanian]; alforfón, trigo sarraceno [Spanish]; Karabuğday [Turkish]; Mạch ba góc, Kiều mạch [Vietnamese]; Bokwiet [Afrikaans]; Gandum kuda [Bahasa Indonesia]; حنطة سوداء [Arabic]; 蕎麥 [Chinese]; כוסמת [Hebrew]; कूटू [Hindi]; ソバ [Japanese]; 메밀 [Korean]; Гречиха посевная [Russian].

Description 

Buckwheat forage are the vegetative parts of the buckwheat (Fagopyrum esculentum) plant grazed or cut for hay or silage making. Buckwheat is an erect annual herb that grows mostly on poor soils. Buckwheat plant is used as fodder for farm animals (Jansen, 2006). Buckwheat foliage can be fed to livestock either green (cut or grazed), dried (hay, straw, stover/stubbles) or ensiled.

Buckwheat forage encompasses the following:

  • buckwheat forage is the entire plant that can be grazed, cut and used fresh or as hay or silage,
  • buckwheat straw is the dry vegetative part of the plant that is harvested with the grain. It can be used for bedding but as it is also palatable to cattle, it can be used as fodder
  • buckwheat stover/stubbles are the leftovers that can be grazed in the field after grain harvest (Lardy et al., 2009),

Morphology

Buckwheat (Fagopyrum esculentum) is an erect annual herb that grows to 120 cm high and has indeterminate growth habit. The root system consists in a shallow taproot and a spreading secondary roots that can go 1 m deep (Kammermeyer, 2016). The stems are hollow and triangular. Its leaves are alternate, simple and entire, with stipules. Lower leaves are petiolated while upper ones are almost sessile. The leafblade is triangular to cordate, 2-10 cm long x 2-10 cm broad. The inflorescence is an axillary or terminal cluster of flowers, combined in false racemes. The flowers are regular, small-sized, rose-red to white in colour. The fruit is a typical triangular, winged nutlet, 5-7.5 mm x 3 mm, grey-brown, dark brown to black in colour. The seed is pale green turning reddish brown almost the same size as the fruit (Jansen, 2006).

Uses

Buckwheat forage can be fed to livestock that eat it readily. The green parts can be fed green, made into hay or ensiled. Buckwheat also make valuable cover crop and provides green manure (Jacquemart et al., 2012; Jansen, 2006). In the USA, buckwheat growers may decide to use their buckwheat as forage rather than grain if seed set was compromised. Buckwheat can be used as a cultivation of substitution to maize in harsh conditions (Kammermeyer, 2016).

Distribution 

Buckwheat (Fagopyrum esculentum) originated from Asia. Its domestication started in the South of China as soon as 2000 to 3000 BCE.
It was then introduced to other Asian countries southward crossing the Himalayas and eastwards to Japan. The arrival of buckwheat in Europe followed the silkroad and cultivation became really popular during the early Middle ages.
During the 17th century, european emigrants brought buckwheat to North America, Argentina, Brazil and South-Africa.

Today, buckwheat is grown worldwide though the production is not at its maximum. This latter was reached during the 19th century and was followed be a decline due to the emergence of cereal crops which made more benefit of fertilizers and had greater yields.
Total area of production in the world was 2.5 million ha in 1961 and it  dropped to 1.44 million ha in 2010 (Jacquemart et al., 2012). It has recently regained interest as buckwheat has favourable nutrient properties for human consumption like the gluten-free proteins and the presence of antioxidative substances. Moreover it has been reported to be a good cover crop (Jacquemart et al., 2012).

Buckwheat (Fagopyrum esculentum) is found in temperate and subtropical areas. It can be grown at higher elevations in the Tropics (1500 m altitude in Ethiopia, for example). Buckwheat can grow in places where the day temperatures are in the range ofg 18-30 °C and the night temperatures drop 5-10°C lower (Jansen, 2006). It requires a dry period at maturity and harvest but it is sensitive to drought at earlier stages because of its shallow roots. If drought occurs during blooming stage, seed production is impaired. Buckwheat does very well on low N, light sandy soils with neutral to slightly acidic pH. It is particularly adapted to recently cleared infertile fields, drained marshland or acidic soils with a high content of decomposing organic matter.
It does not well on rich soils since lush growth causes lodging and reduces seed set. However, if it is grown to produce biomass and not seed, rich heavy soils keep being valuable (Jacquemart et al., 2012).

Forage management 

Buckwheat (Fagopyrum esculentum) is a fast growing plant that can be cultivated as a summer or a winter crop in rotation with cereals or also be intercropped with vegetables (Jansen, 2006). However, it is not recommended to sow buckwheat in mixed stand with legumes. Buckwheat reaches its full height only 4-6 weeks after sowing and sets seeds within 70-130 days after emergence. The indeterminate growth habit of buckwheat is a constraint of the crop as it is never easy to determine when best harvest of the grain can be obtained.

Cultivation

Buckwheat seeds should be sown on a clean 5 cm depth firm, well-prepared seed-bed. It can be drilled at 40-60 kg/ha to 2- 4 cm deep in rows spaced 30 cm apart or it can be broadcast at higher density (+10-20 kg seeds/ha) and then harrowed to cover with topsoil (Jansen, 2006). Though weeds are generallly not a problem, fast growing weeds may however be an issue and this is alleviated by sowing at higher density and harrowing 4 weeks after sowing. This operation removes weeds and buckweat plant but the high density of buckwheat allows it to remain in good quantity.
If sown at lower density the plant will make more branches and seeds.

Yields

In Turkey, at harvest time, the green matter of buckwheat was above 27 tonnes/ha and hay yield was about 7.5-8.5 tonnes/ha. It was reported that yields increased by delaying harvest times (Kara, 2014).

Harvest

When buckwheat is used as a forage crop, it should be harvested prior to maturity as mature forage has lower protein content and digestibility (Lardy et al., 2009). After grain harvest, the straw can also be used as a beeding material but due to its palatability it is often eaten (Lardy et al, 2009).

Environmental impact 

High quality cover crop and rotational effect

Buckwheat germinates and grows quickly, soon developing a dense, shading canopy that smothers weeds effectively (Kammermeyer, 2016; Valenzuela et al., 2002). It also produces high amount of biomass that can be ploughed into the soil for high N and high P manure (Jacquemart et al., 2012). Buckwheat has an excellent "rotational effect". It is also a phosphorus scavenger: its roots exsude chemical substances that extract inorganic phosphorus from the soil and they make reserves of phosphorus. Roots residues thus make phosphorus more available to the next crop and also return considerable levels of phosphorus to the soil (Valenzuela et al., 2002).

Weed and diseases control

Buckwheat plant has some allelopathic properties that prevent weed development (Jacquemart et al., 2012). Buckwheat residues were also reported to have allelopathic effects on weeds (Valenzuela et al., 2002). Spreading 2 tonnes of buckwheat pellets before rice plantation was found to reduce weed by 80% in rice field and thus to increase rice yield by 20% (Eom et al., 1999; Iqbal et al., 2002). Buckwheat also decreases disease load (Jacquemart et al., 2012).

Interaction with insects

Buckwheat with its continuous blooming attracts many kinds of insects including pest predators like syrphids. It is a good foraging plant for bees that make tasteful honey from its nectar. It has been reported taht 1 ha of buckwheat could provide 125-300 kg honey.
Buckwheat long lasting flowering period is also valuable for beekeepers as the bees still find food on buckwheat when other melliferous plants have disappeared (Naukim, 1998 and Olson, 2001 cited by Jacquemart et al., 2012).

Nutritional aspects
Nutritional attributes 

Buckwheat contains also different secondary metabolites as vitamins and polyphenols, which contribute to animal health and product quality. Buckwheat contains high concentrations of condensed tannins and total phenolic compounds; rutin and quercetin being the main phenolic compounds (Kalinova et al., 2006; Christa et al., 2008; Herremans et al., 2018). High concentrations in α-tocopherols of buckwheat whole plants have also be reported (Kalinova et al., 2006; Maxin et al., 2017).

Potential constraints 

Skin sensitization

Buckwheat contains fagopyrin, a flavonoid that causes skin sensitization in animals fed on buckwheat. The content of fagopyrin is higher in green parts of the plants and cattle, sheep and goats are thus more likely to suffer from this health condition than monogastric animals fed on grain. Skin rash can develop on light-colored animals if they are fed during a long time on a ration that contains more than 20-25% of the concentrate content in buckwheat and if they are in the sun (Lardy et al., 2009; Björkman et al., 2000). In Lithuania, where buckwheat chaff and forage was a main feed for pigs, it resulted in the selection of a colored breed that was not sensitive to skin sensitization due to buckwheat  (OSU, 1996).

Ruminants 

Fresh whole buckwheat plant has high protein content at leafy growth stage (19% CP, Kälber et al., 2014; Maxin et al., 2017) and a low fiber content (29% CP, Kälber et al., 2014; Maxin et al., 2017). However, protein content declines rapidly with maturity (12% CP; Leiber, 2012; Kälber et al., 2011 and 2014; Maxin et al., 2017) while fibre content increases (47%; Leiber et al., 2012; Kälber et al., 2011 and 2014; Maxin et al., 2017).

In vitro organic matter digestibility (IVOMD) declines also with maturity with 91% and 78% at respectively at vegetative and flowering stage (Herremans et al., 2018).

Dairy cows
Fresh buckwheat forage

When mixed with ryegrass as part of a cow’s diet, fresh buckwheat resulted in higher intake and similar milk yield in comparison to ryegrass alone; it also improved transfer of alpha-linolenic fatty acid from the diet to milk (Kälber et al., 2014; Kälber et al., 2011). Milk yields were, however, lower when buckwheat was fed at flowering stage than when fed at vegetative stage (Kälber et al., 2014).

Buckwheat silage

Dry matter intake and milk yield and composition of dairy cows fed buckwheat silage were similar to dairy cows fed ryegrass silage (Kälber et al., 2012a). However, milk from dairy cows receiving buckwheat had higher proportion in linoleic acid and total PUFA compared to milk from dairy cows receiving ryegrass silage (Kälber et al., 2013).

For cheese-making, feeding cows with buckwheat silage shortened rennet coagulation time of the milk by 26% and tended to increase curd firmness by 29% (Kälber et al., 2013).

Buckwheat hay, straw and stubbles

Buckwheat hay could be consumed and was reported to be palatable (Lardy et al., 2009). Buckwheat straw is used as bedding materials but it is palatable and often eaten. If used as fodder it should be limited to 25% of the ration (Lardy et al., 2009)

Grazing buckwheat stubbles resulted in low acceptability and nutritive value in sheep (Mulholland et al., 1979).

Other ruminants

After getting used to buckwheat, deer readily graze buckwheat (Kammermeyer, 2016).

Poultry 

Buckwheat plant could be grown in association with phacelia (Phacelia tanacetifolia) and  flax (Linum usitatissimum) and grazed by free range poultry. It was shown that the mixture of forbs was well accepted by the hens without an effect on performance (Horsted et al., 2006).

Rabbits 

Buckwheat forage

No information seems available in the international literature of the use of buckwheat as green or dry (hay) forage in rabbit feeding. However wild rabbit may damage buckwheat crops as observed in Tibetan area (Scheucher, 2004). This is a sign that green buckwheat plant is appreciated by rabbits, and thus may be a potential source of forage for rabbits. The leaves protein  content is about 10 to 16% DM and that of crude fibre about 17-22% (Duval, 1995; Ratan et al., 2011). As the grain’s proteins, those of buckwheat leaves are rich in lysine (5.8 % proteins) and poor in sulphur amino acids (Lahanov et al., 2004).

Buckwheat byproducts

As mentioned for the whole plant, no information seems available in the international literature of the use of buckwheat byproducts in rabbit feeding. However buckwheat straw is frequently used in ruminant feeding with success (Scheucher, 2004). It can thus be considered as potential sources of raw materials usable in rabbit feeding.

Straw can be a source of fibre (45-48% crude fibre in DM) but with a non negligible content of crude proteins : 5.5-6.0% in dry matter (Ratan et al., 2011). Buckwheat middlings should be considered as a potential source of proteins : 33-34% crude proteins with a low content of fibre (10% ADF in DM) (Waller, 2010; Ratan et al., 2011).

A special mention must be done to buckwheat hulls (or husks), which are generally used as fuel by farmers or to fulfil pillows, but also used to feed ruminants when the stock of buckwheat straw is exhausted (Zemnukhova et al., 2004, Ratan et al., 2011). Buckwheat hulls are composed mainly of fibre : 80% total fibre and contains about 30% of lignins (Ciepielewska et al , 2004). Thus, it may be considered as a potential source of lignins for rabbit balanced diets (one of the richest among all raw material available). However new direct experiments should be done with buckwheat hulls, since ancient experiments (Kubo et al., 1938 – 1939) mentioned physiological alterations following buckwheat husks distribution to rabbits, rats or mice (true effect of buckwheat husks or consequence on a mycotoxins present in the husks batch used for the experiment ?).

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References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. https://www.feedipedia.org/node/25478 Last updated on August 9, 2019, 15:33