Buckwheat
Buckwheat, Fagopyrum esculentum Moench, is a species of annual flowering plant in the Polygonaceae family, cultivated for its seeds, which are used for human and animal consumption.
Despite its common name of buckwheat, buckwheat is not a species of the genus Triticum (a genus grouping together the varieties of wheat), nor even a species of grass. It is gluten-free, which makes it difficult to use in bread-making or pasta-making. It is, however, classified as a cereal - although not botanically - or as a pseudo-cereal.
It is known by various common names : buckwheat, buckwheat knotweed, buckwheat, barbary wheat, bucail, carabin, but also black wheat.
Description
- Buckwheat is an annual plant with an upright stem, 20 to 70 cm high.
- The leaves are inverted heart-shaped and rather soft. The upper leaves are sessile, while the lower ones are fairly long-stalked.
- The small, white or pink flowers are grouped in tight clusters. They have eight stamens and three styles. As in other species of the Fagopyrum genus, there are two floral morphologies : these are distylic species.
- The fruits are three-angled achenes containing a single seed. They ripen at very different times, which makes harvesting rather tricky. Rich in protein, they contain all the essential amino acids and are thought to have numerous nutritional properties. It is a highly nutritious grain, which is also rich in soluble fibre and antioxidant compounds.
Growing itinerary
Buckwheat is sown in France from mid-May to early July (as a catch crop) and until August in subtropical Japan (sometimes as a cover crop), to avoid the frosts it cannot withstand. Buckwheat is a plant that needs heat for rapid, uniform emergence (within a week) and plenty of moisture.
For a grain harvest in France, it is preferable not to sow after 15 June, as high temperatures at flowering can cause flower abortion (coulure) and reduce yield. Similarly, bee populations are generally insufficient, so it is advisable to place two to five hives per hectare close to the plots. You can sow around 40 kg/ha of a variety like Harpe with a cereal drill.
Buckwheat exports few mineral elements, so no fertiliser is generally applied, even organic. Too muchnitrogen can lead to lodging or the green parts developing to the detriment of the seeds. Previous crops with high residue levels and soils rich in organic matter should therefore be avoided.
The main predators are pigeons. There are generally no other pests or diseases.
Buckwheat easily dominates competing grasses after the 2 true leaf stage, and its roots emit toxic substances(allelopathic effect). It is therefore important to ensure that buckwheat reaches this stage on clean soil, if necessary by planting a false seedbed before careful sowing. Weeding, even mechanical weeding, is not normally carried out, as the plant breaks easily.
Buckwheat is harvested between mid-September and mid-October. It is unusual in that it does not ripen uniformly, so losses can be high at harvest time, especially with the use of a combine harvester. Harvesting takes place when the stalks are red and three quarters of the grains are ripe at 25 % moisture content. They are then dried to 15 % for good conservation. Yields vary from 0 to 30 dry quintals for a cycle of 2 to 5 months.
Technical aspects
| Interventions | Stage/period | Advice |
|---|---|---|
| Choice of plot | Not very restrictive, suitable for superficial soils | |
| Soil preparation | Optionalploughing, as soon as a sufficiently fine seedbed can be made. | |
| Sowing | mid-May to early June, sowing in catch crop possible | Soil clean at sowing and warmed (10°C) Density 30 to 40 kg/ha (aim for 150 to 200 g/m²) |
| Fertilisation | Nitrogen fertilisation not recommended | |
| Weed control | Sensitive stage from emergence to 2 true leaves Grass control possible before flowering | |
| Diseases | ||
| Harvest | Late September to mid-October | When ¾ of the seeds are mature (indeterminate flowering). Often 20-25% humidity. |
| Storage | Dry to 14% H2O. |
Economic aspects of cultivation
- Surface area : around 5,000 ha in France
- Production area : Brittany, Limousin, Centre, Burgundy
- Markets : human food
- Market saturated at present
- Opportunistic crop
| Charges opérationnelles en €/ha | Produit | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||
| Total : 113€ | Total : 175 à 700 € |
Changes in area under cultivation
In France, buckwheat almost disappeared, covering 700,000 ha in France in the 19th century and 160,000 ha in Brittany in the mid-1960s, when copper deficiency in the soil made it impossible to grow any cereal except rye. Rye was replaced bybarley, wheat and maize, which are more profitable in a system of intensive fertilisation. However, margins can be similar per hectare because of the very low input itinerary. The FAO reports that 30,000 hectares are grown in France.
For some years now, however, buckwheat has been grown by farmers practising conservation agriculture and organic farming. Its high covering power, which helps reduce weed pressure throughout the rotation, and its ability to save nitrogen make it an interesting plant, particularly for intercropping(intermediate nitrate trapcrops ).
Benefits
Interest in human food
- Buckwheat's distinguishing features are its high phenolic compound content and the absence in its protein component of water-insoluble proteins capable of forming gluten.
- As a result, nutritionists class buckwheat as a pseudo-cereal, likeamaranth and quinoa, suitable for the gluten-free diet . Its seeds can be ground into flour and eaten in a similar way to cereals.
- It is one of the edible plant species that contains most of the essential amino acids in sufficient quantities, unlike modern varieties of wheat and hybridspelt, which may have lost this characteristic through cross-breeding and selection. Despite lower yields and a higher price per kilo, buckwheat is, in this respect, more interesting than wheat and spelt.
Interest in animal feed
- Buckwheat (grain or fodder) can be used as animal feed. Buckwheat grains have excellent protein quality, with a much higher proportion of lysine than cereals. However, its energy value is lower than that of barley. Given these characteristics, the best way to use buckwheat would be to mix it with conventional cereals.
- Buckwheat hulls (or straw) are not easily digestible and are not much appreciated by ruminants.
- Buckwheat is used as a cover crop for game, sown alone or in a mixture.
- Buckwheat is a melliferous plant.
Agronomic benefits
- It is a cleaning plant that limits the presence of invasive plants by occupying the soil. When combined with mycorrhizae, its roots mobilise large quantities of phosphorus and calcium. It can be used as a service plant for early planting of clover, lucerne or even rape.
- Easy to germinate, smothering weeds and sensitive to frost, buckwheat is considered an excellent green manure and can be used as a ground cover. It should be sown in early summer and destroyed before the seeds ripen.
Photo gallery
Annexes
Case study
