Species: Vicia faba L.
Synonym: Faba vulgaris Moench.
French: Fève, Gorgane; English: Broad bean, English bean, Horse bean; Spanish: Haba; German: Gartenbohne, Saubohne, Puffbohne.
Origin and diffusion
Broad bean as a food plant was used by man in the Mediterranean and Middle Eastern area in very remote times. In Italy the bean surface has dropped below 50,000 ha, mainly located in the southern and island regions.
The fava bean is cultivated for its grain which, dry or fresh, is used as food for humans, and for animals. The plant is grown for fodder (grasshopper) and for green manure. In historical antiquity, throughout the Middle Ages and until the last century, dried beans cooked in various ways formed the main food protein base of many populations, especially those of southern Italy. In recent times, the consumption of dry seeds has decreased, while the use of fresh, preserved, canned or frozen immature grains is still widespread in human nutrition.
Fava - Vicia faba L. variety Acquadulce Improved of the Cascine (photo website)
Bean pods - Vicia faba L. (photo website)
The broad bean is a legume belonging to the Vicieae tribe; its botanical name is Vicia faba (or also Faba vulgaris). Within the species, three botanical varieties are distinguishable based on the size of the seeds:
-Vicia faba maior, large beans, which produces flattened and large seeds (1,000 seeds weigh from 1,000 to 2,500 g), used for human consumption;
- Vicia faba minor, field bean or small bean, whose seeds are round and relatively small (1,000 seeds weigh less than 700 g) and are used to sow herb and green manure (since they save seed, compared to other varieties) and also as concentrates in feeding of cattle.
- Vicia faba equina, favetta or horse bean, equipped with medium-sized flattened seeds (1,000 seeds weigh from 700 to 1000 g) which are used for feeding livestock and, today, also for man as fresh canned or frozen grain.
The broad bean is an annual plant, rapidly developing, erect, glabrous, gray-green in color, with indeterminate development. The root is taproot, rich in bulky tubercles. The erect stems, fistulous, quadrangular, up to 1.50 m high (average 0.80-1.00 m) are not branched, but sometimes there can be a very limited bunching with secondary stems at the base of the main one.
The leaves are alternate, paripinnate, composed of two or three pairs of whole elliptic sessile leaflets, with the terminal leaflet transformed into an inconspicuous appendix but attributable to the cirrus that characterizes the leaves of the Vicieae. The flowers are formed in numbers from 1 to 6 on a short raceme that arises in the axilla of the middle and upper leaves of the stem. The flowers are almost sessile, rather showy (length 25 mm), the corolla has white and sometimes purple petals and, almost always, with a characteristic dark spot on the wings. The ovary is pubescent, elongated and ends with a stigma at the head, it contains from 2 to 10 eggs.
In the field bean fertilization can be allogama, with cross-pollination carried out by hymenoptera (bees and bumblebees), or autogamous. The fertilized ovary develops in an elongated pod, green in its immature state, brown when ripe and dry, it contains from 2 to 10 seeds of generally light greenish color, but also brown or violet, with large, elongated and generally dark hilus .
The shape and size of the seeds are, as we have seen, very different in the different varieties.
Favino - Vicia faba minor L. (photo Francesco Sodi)
Field beans - Vicia faba minor L. (photo Francesco Sodi)
The bean germinates with acceptable readiness already with soil temperatures around 5 ° C; in these conditions the emergency occurs in 15-20 days. The resistance of the bean to cold is limited: in the early vegetative stages) stage of 4-5 leaves), when the bean has the maximum resistance, frosts of –6 ° C are fatal to most varieties; only certain types of field beans resist up to -15 ° C.
During flowering, the resistance of the bean to frost is even less. In addition, at this stage rather low average temperatures, although not fatal for the survival of the plant, can compromise the fruit setting either directly, disturbing the physiology of the anthesis, or indirectly by hindering the flight of the pollinators. During flowering, high temperatures are to be feared, which if they exceed 25 ° C, cause the flowers to "drip".
From a water point of view, the bean is a strong water consumer and finds the most important limiting factor of yields in the water deficiency during the grains phase, particularly in the case of spring sowing. The drought causes the flowers to leak and the number of seeds per pod and the weight of 1,000 seeds is reduced.
The bean adapts well to heavy, clayey, clayey-calcareous soils; it avoids the loose and humus-poor, organic ones, subject to stagnant water. The pH that best suits the bean is the sub-alkaline one.
The main objectives of the genetic improvement of the bean are: increase in productivity (especially through regularity of production), earliness, resistance to certain adversities (cold, viruses), simultaneous maturation of the grain, quality of the grain.
The current varieties are either populations subjected to mass selection or synthetic varieties. Some promising prospects seem to be offered by the establishment of "F1 hybrids".
Thanks to the fact that it is a legume, that is weeded and that frees the soil very early, so as to allow an excellent preparation for the wheat, the bean is an excellent improvement crop, which constitutes an excellent precession for the wheat; its place in the rotation is therefore between two cereals.
It can be considered that the cereal following the bean finds a nitrogen residue, brought from the legumes, of the order of 40-50 Kg / ha.
In good cultivation conditions, after collecting the grain, the bean leaves a quantity of residues of the order of 4-5 t / ha of dry matter.
The rational preparation of the soil for the bean consists of a deep plowing (0.4-0.5 m) which favors the deepening of the roots and therefore the exploration and exploitation of the deeper water and nutritional resources.
It is not necessary to prepare a very refined sowing bed: the considerable size of the seeds ensures that contact with the soil is ensured even if a certain stickiness persists.
The mineral fertilization of the bean should be based mainly on phosphorus, since like all legumes it is particularly sensitive and reactive to this element: 60-80 kg / ha of P2O5 are the dose to be made.
Potassium generally abounds in clay soils where the bean should find its home.
As far as nitrogen is concerned, the bean is in fact self-sufficient, thanks to the symbiosis with Bacillus radicicola, so nitrogen fertilization is not necessary.
Autumn sowing should be done so that the seedlings have reached the stage of 3-5 leaves before the cold arrives. In the central regions the optimal time of sowing is between October and November; in the southern ones the second decade of November.
Spring sowing (actually at the end of winter) must be done as soon as possible to anticipate the cycle and escape the drought.
The seed quantity must be such as to ensure 12-15 plants per square meter in the case of coarse beans, 25-35 in the case of broad beans and 40-60 in the case of field beans.
The seed quantities must be calculated on the basis of the average weight of the seeds: they generally oscillate between 200-300 kg / ha or more. Sowing is generally done with universal seeders with rows 0.50 m apart in the case of broad beans and 0.35-0.40 m in the case of the field bean. The sowing must be rather deep: 60-80 mm in the case of coarse beans, 40-50 mm in the case of broad beans and field beans. Orbanche attacks appear to decrease with deep seeding. In the Ortensian culture the broad-seeded bean is sown in postarelle, placing 3-5 seeds per hole in 4-5 small holes per square meter.
The seed must always be treated with tanning products to protect the seedlings from the attacks of Rhizoctonia, Pythium and Phytophtora. In open field cultivation, dense sowing is convenient because it causes the insertion of the lower pods to increase, which is advantageous for the combine harvesting, which in this way gives rise to less grain losses.
Weeding and crop care
Traditionally the fava bean was a cultivated crop. It can currently be chemically weeded in pre-sowing, pre-emergency or post-emergency.
Among the cultivation treatments that (not always) we do we mention the weeding, a slight tamping, the topping.
Collection and use
The collection of pods from the vegetable garden for fresh consumption is done by hand.
The immature seeds for canning and freezing are harvested with fixed or self-propelled ginners, when they have reached the right tenderometric degree.
The tenderometric degree is provided by a special device, called a tenderometer, which measures the resistance of the seed to be perforated by a tip. The optimal tenderometric values are normally 95-105 for freezing beans, 115-125 for canning beans.
The collection of dry seeds is done when the plant is completely dry. The large beans cannot be harvested with combine harvesters, except with poor quality results (seed breakage). Only the field bean is collected easily enough by means of a suitably regulated combine.
The harvest time is mid-June in southern Italy, late June in central Italy, mid-July in northern Italy with spring sowing.
The production of pods for fresh consumption (vegetable fava beans) is in the order of 20-30 t / ha.
The production of fresh seeds for the industry is considered good when it reaches 5-6 t / ha.
The production of dry seeds, although theoretically it could exceed 5 t / ha, in practice is much lower: 2-3 t / ha are the most frequent average productions in Italy, with high risks of having in some years even much lower yields due to factors not or poorly controlled by man (cold, drought, attacks of rust or aphids, virosis).
Dried fava beans have a high protein content: their average composition is in fact the following: dry matter 85%, nitrogenous substances 23-26%, ash 3%, fats 1.2%, raw fiber 7%, extractives in nitrogen 48%.
Orobanche, fearful adversity of the Fava (photo Francesco Sodi)
Adversity and pests
The main and most frequent adversities that the broad bean may incur are the following.
- Plant pests
Anthracnose: the most serious attacks are those on the pods on which it forms necrotic and depressed, blackish notches, which extend to the seeds in formation.
Rust: occurs on leaves and stems with the appearance of rusty pustules.
Mosaic: several viruses cause mosaic diseases on the bean.
Orobanche: it is a parasitic phanerogam that inflicts its austorius in the roots of the bean with which it sucks the sap processed by the legumes.
- Animal parasites
Black aphid: infests the bean, and many other plants, forming colonies of black aphids that lead the plants to serious deterioration in addition to transmitting some virosis.
Tonchio: the adults lay their eggs on the young pods; the newborn larvae pierce the carpels to reach the seeds inside which they develop by digging tunnels; at the end of the cycle the adults flicker from the seeds piercing the seminal integuments.