Leguminous crops, or grain legumes, often identified as pulse crops, are a group of agricultural cultivated plants belonging to the legume family (Fabaceae).
Main leguminous crops:
- peas;
- lens (lentils);
- vetch (Vicia);
- beans (Phaseolus);
- mash (Mung bean);
- vigna;
- soybean;
- lathyrus;
- cicer;
- fodder beans;
- lupine;
- peanut.
The main difference between legumes and cereal crops is that they produce more protein per unit area, the quality and digestibility of which is higher, give the cheapest protein. Their peculiarity is inclusion in the biological cycle of air nitrogen. The fixation of air nitrogen occurs as a result of symbiosis of leguminous plants with Rhizobium nodule bacteria.
Contents
- Economic importance
- Cultivation areas
- Taxonomy
- Botanical description
- Chemical composition of grain
- Nitrogen fixation
- Biological features
- Growth phases (phenological phases)
- Intensive cultivation technology
- Vegetable legumes
- Canavalia ensiformis
- Canavalia gladiata
- Pigeon pea (Cajanus cajan)
- Guar (Cyamopsis tetragonolobus)
- Lablab purpureus
- Australian peas (Dolichos lignosus)
- Hicama (Pachyrhizus erosus)
- Winged beans (Psophocarpus tetragonolobus)
- Fenugreek (Trigonella foenum-graceum)
- Maram bean (Tylosema esculentum)
- Moth bean (Vigna aconitifolia)
- Adzuki (Vigna angularis)
- Urd (Vigna mungo)
- Mung bean (Vigna radiata)
- Bambara groundnut (Vigna subterranea)
- Rice bean (Vigna umbellata)
- Cowpea (Vigna unguiculata)
- Background of current types
- Sources
- Leguminous crops (Русская версия)
Economic importance
Grain legumes are the second most important source of food in the world after cereals. The term “legumes” refers to the edible seeds of pod plants.
Grain legumes are cultivated to produce seeds with high protein content. They are divided into food, fodder, technical and universal crops. Beans and lentils are characterized by high taste and culinary qualities and are used in human food. Lathyrus, cicer, fodder beans, white and yellow lupine are used for the production of combined fodder, although in some countries cicer and white lupine seeds are used as food. Soybeans were until recently used as a technical oilseed crop. At present, it is mostly used as a forage and food crop, retaining the importance of an oil-bearing raw material. Soybean has no equal in versatility of use among field crops. Peas are also noted for their universal use as food and feed for animals.
According to zoo-technical regulations 1 fodder unit should contain 110-115 g of digestible protein, the actual content of 96 g, i.e. 83-87% of the norm. Protein deficiency results in overconsumption of fodder by 20-30% per unit of livestock production and is one of the obstacles to further increase of animal productivity.
Grain legumes, having a high fodder value, also improve the absorption of animal feed of other crops with low protein content.
Table. Fodder value of leguminous crops (according to M.F. Tomme et al., 1970)
| Soybean | ||||||
| Lupine yellow | ||||||
| Fodder beans | ||||||
| Lathyrus | ||||||
| Pea | ||||||
Protein content in grain legume crops is determined by variety and growing area, but primarily by the conditions of symbiotic nitrogen fixation by air, i.e. agrochemical parameters of soil and moisture availability of plants. On acidic, nutrient-poor soils, nitrogen fixation is inactive or does not take place at all, plants experience nitrogen starvation, the yield and crude protein content in green mass and seeds decreases sharply. A lack of moisture on nitrogen-poor soils has a similar effect. For these reasons, the amount of protein in the same crop is 10-15%.
Table. Crude protein content in seeds and green mass of leguminous crops (G.V. Bodnar, G.T. Lavrinenko, 1977).
| Northwest | Seeds | ||
| Central | Seeds | ||
| Green mass | |||
| Volga | Seeds | ||
| Central Black Earth | Seeds | ||
| Central | Seeds | ||
| Far East | Seeds | ||
| Northwest | Seeds | ||
| Green mass | |||
| Central | Seeds | ||
| Green mass | |||
| Western Siberia | Seeds | ||
| Green mass | |||
| Volga | Seeds | ||
| Ural | Seeds | ||
| North Caucasus | Seeds | ||
The protein of grain legume seeds is notable for its usefulness as a fodder. The content of essential amino acids is 1.5-3 times higher than in the protein of cereal crops. For example, 1 kg of soybean seeds contains 6 times more lysine than 1 kg of wheat.
Table. Content of essential amino acids in grain legume seeds, g/kg dry matter (M.F. Tomme, R.V. Martynenko, 1972)
| Lysine | ||||||
| Methionine | ||||||
| Cystine | ||||||
| Arginine | ||||||
| Leucine | ||||||
| Phenylalanine | ||||||
| Threonine | ||||||
| Valine | ||||||
| Tryptophan | ||||||
| Histidine | ||||||
| Amount |
Seeds of some leguminous plants contain a sufficiently high amount of fat: in soybean – 16-27%, cicer – about 5%, white lupine – up to 10%, which also contributes to the feed value.
According to their nutritive value, 1 kg of grain is equal to 1.1-1.4 fodder units, the digestible protein content being 160-200 g. The vegetative mass is used for making hay, haylage, grass meal and for green fodder. Silage green mass of grain legumes with corn or other crops increases the protein balance of silage. Mixed crops of legumes and grain crops increase the fodder value of the latter.
The industrial importance of leguminous crops is that the seeds are used to produce cereals and flour, confectionery, preserves, oils, food and feed concentrates. Unripe seeds and fruits are used to make canned vegetables. Soybean seed oil is of food and technical value. The enzyme urease and protein in beans are used in medicine. Soybean and chinna seeds are a raw material for the production of casein, glue and plastics.
Agronomic importance lies in providing a large harvest of plant protein and are less nitrogen-depleting than nonlegume crops. Although symbiotically fixed nitrogen is alienated with the crop, more nitrogen remains with the organic residues of legumes than with the residues of other crops, so they have proven to be good predecessors in the rotation. The root system of many legumes is capable of assimilating nutrients difficult for other crops, such as tri-substituted phosphates.
Alkaloid varieties of yellow lupine are cultivated as a green fertilizer on sandy soils, narrow-leaved lupine on loamy soils. Yields of green mass up to 30 tons/ha are formed. Some leguminous crops are grown as intercrops in different areas of the country for green fodder and to increase soil fertility.
Importance of vegetable legumes
Vegetable legumes are considered a useful source of nutrients and are recommended by health organizations and nutritionists as a staple food. They are rich sources of vitamins, minerals and carbohydrates in the human diet and a useful source of protein and energy in livestock diets. They are an important source of protein for vegetarians and have a low glycemic index (Rizkalla et al., 2002). Legumes are an important food in tropical and subtropical countries, where they are second only to cereals as a source of protein. They are also recognized as a food with significant potential health benefits. They contain complex carbohydrates (dietary fiber, resistant starch and oligosaccharides), protein with a good amino acid profile (high in lysine), important vitamins such as B vitamins, folate and iron, and antioxidants and polyphenols.
Before consumption, legumes are harvested, processed and processed in a variety of ways and subjected to several primary and secondary processes, such as peeling, hulling, husking, chopping and crushing. In many developed countries, there has been very little growth in interest in the use of whole legumes and their ground constituents, especially flours and fractions such as protein, starch and fiber, and their use in food products. There are new developments in the use of processing technologies such as extrusion cooking, including these ingredients for specialty foods such as pasta, baby food, snacks, dry soups, and pet food. In addition, research is ongoing on the use of legume ingredients in pharmaceutical or “nutraceutical” products (Carbonaro, 2011).
Cultivation areas
In the world agriculture leguminous crops occupy 135-160 million hectares, which is about 13% of grain crops. The largest areas of cultivation are in India and China. The gross yield is 230 million tons, or 9 times less than that of grain crops. The average yield in the world is 1.5 t/ha.
In the USSR, leguminous crops in 1984 occupied 6.7 million ha, in Russia – 1.2-2.0 million ha with yields in the 1990s of 1.2-1.6 t/ha. Gross yield is 1.8 million tons. Peas are the most common crop in Russia. The USSR ranked first in the world by sown area, which amounted to 4.95 million hectares and the collection of pea seeds. Soybeans and lupine also accounted for a large share of the sown area. Beans, lentils, cicer, lathyrus and fodder beans are cultivated in small areas.
Dry areas of the steppe zone are sown with drought-resistant cicer and lathyrus; fertile clay and loamy soils of the Baltic, Polesie, central part of the forest zone and the Urals are the high-yielding fodder beans; yellow fodder lupine is sown on sandy soils.
In the Far East, in some areas of the North Caucasus, Ukraine, Moldova and the Lower Volga region, soybean is the most valuable crop.
Taxonomy
The legume family (Fabaceae or Leguminosae) is a vast and very large botanical family consisting of more than 450 genera and over 12,000 species. Many species are important as food sources for humans and animals.
Legumes have been cultivated in various parts of the world for over 6,000 years. Wild forms of many modern legumes do not occur, although, according to Vavilov, some legume species seem to be related to certain identified centers of origin. For example, he attributed some species of Phaseolus to the New World (North and South America) and some others identified as Phaseolus to the Old World. However, those species that were assigned to the Old World and previously identified as Phaseolus are now correctly classified in the large and widespread genus Vigna.
The Fabaceae family has been divided into three main subfamilies, Caesalpinioideae, Mimosoideae, and Papilionoideae, but recently Caesalpinioideae has been further divided into several genera, including the Cercideae tribe (Group, 2013), which contains a small group of tropical and temperate woody plants with flowers similar to those of Papilionoideae.
The subfamily Mimosoideae includes 82 genera and over 3,200 species. Like Caesalpinioideae, the leguminous Mimosoideae are mostly tropical woody plants, but there are several species from temperate climates. Woody perennial legumes are widespread, and many species in this group have the ability to fix atmospheric nitrogen, so they have colonized many areas of the world with low soil nutrients. They are also used commercially for wood or various extracts such as gum and dyes.
The subfamily Papilionoideae (or Faboideae) is the largest group of legumes, including about 650 genera and nearly 19,000 species (Lewis et al., 2005).
As members of the large-seeded legume group of the Fabaceae family, peas and beans belong to several distinct taxonomic groups. Among them, three lineages have a number of groups that contain cultivated plants.
The most economically important group is Phaseoleae, which includes soybean (Glycine max), phosol species (Phaseolus), and cowpea (Vigna unguiculata). The second group, Genisteae, contains Lupinus, of which there are three economically important grain legume species: Lupinus albus (white lupine), Lupinus angustifolium (narrow-leaved lupine) and Lupinus luteus (yellow lupine). The third taxonomic group, Fabeae, contains the so-called cold season legumes, which include peas (Pisum sativum) and horse beans (Vicia faba) as well as lentils (Lens spp.) and sweet peas (Lathyrus spp.).
Fabacaea:
- Papilionoidaea:
- Genisteae:
- Lupinus
- Phaseoleae:
- Glycine
- Vigna
- Phaseolus
- Fabeae:
- Lathyrus
- Lens
- Pisum
- Vicia
- Genisteae:
- Mimosoideae
- Caesalpinioideae
Botanical description
Legumes are dicotyledonous annuals and perennials; most cultivated vegetable and grain legumes are annuals.
Root system
The root system of leguminous crops has the main tap root, the depth of penetration reaches 2 m, and numerous lateral roots of the second, third and subsequent orders, placed mainly in the arable layer of soil. On chernozems and some other soils 70-75% of root system is placed in arable layer, on sod-podzolic soils the share of roots in arable layer is 85-95%, on soils with thick podzolic layer – up to 100%. The optimum soil volume mass for normal root system development is 1-1.3 g/cm3.
Stem
The stem has a different structure. In soybeans, lupines, beans, cicer, and bush beans, the stems are upright throughout the growing season. Peas, vetch, lentils, lathyrus and some forms of beans have loping stems. The apical leaflets of the pinnate leaves are reduced to tendrils, which the plants use to cling to one another. The stems are held upright until the seeds are completely full. By the time they reach maturity, the stems are lodged.
Leaf
As a rule, the leaves are alternate and mostly compound.
According to the structure of the leaves, leguminous crops are divided into:
- plants with pinnate leaves – peas, lentils, chickpeas, chickpeas, beans;
- plants with trifoliate leaves – beans, soybeans;
- sessile leaflets plants – lupine.
These groups differ in the nature of initial growth and peculiarities of agrotechnics. Plants with pinnate leaves germinate at the expense of the epicothelium, so they do not bring seeds to the surface, allowing for deeper embedding of seeds and harrowing before and after emergence.
Pea, Pisum sativum, has hypogeal germination, in which the cotyledons and seed coat remain under the soil due to limited elongation of the hypocotyl. The epicotyle is fully differentiated before germination and breaks through the soil. Epigeal germination is characteristic of the common bean, Phaseolus vulgaris, where the cotyledons appear above the surface due to rapid elongation of the hypocotyl. The orientation of the seed in the soil can affect the growth of the hypocotyl and thus the timing and success of seedling emergence. The seed coat sometimes remains in the soil or may be carried higher and crumbled as the cotyledons unfold. The peanut, Arachis hypogaea, exhibits a different behavior in which the cotyledons remain on the surface rather than under or above the soil. Further growth occurs due to elongation of the above-ground epicotyl; the length of the hypocotyl depends on the sowing depth.
Plants of other groups grow first by extending the subcotyledonous knee (hypocotyl) and bring to the surface of the seedling. They require finer seed embedding, harrowing before sprouting is not carried out.
Flower
Flowers are perfect, irregular, characteristically butterfly-shaped, the perianth is double. The corolla consists of petals of different size and shape (boat, sail, and wings): a vertical dorsal petal (sail), two lateral petals (wings), and two lower petals, often more or less united in a keel-like structure.
The flower contains 10 stamens and one pistil with a single ovary and several testes. The corolla is white to bright red or purple. For most legumes, flowers are gathered in inflorescences at the top of the main stem and lateral shoots.
Self-pollination is common; when cross-pollination occurs, bees are often the main agent.
Fruit
The fruit is a bean, of varying size and shape, often incorrectly called a silique. It opens with two valves and contains several seeds. After ripening, for most species the beans crack along the longitudinal seams, the valves twist and the seeds are scattered. In cicer and some species and varieties of lupine, the beans do not crack. Varieties of beans, soybeans, and lathyrus with weak bean cracking have been bred.
Seeds
Seeds vary in shape (from round to flat and angular), size and color. The seed consists of a seed coat and a germ. At the place where the seed is attached to the fruit, the seed welt is preserved; in beans, there are tubercles of halase and micropiles. The embryo consists of two fleshy cotyledons and a germinal root and kidney between them, from which the above-ground part of the plant is then formed. The cotyledon represents the germ leaves where the nutrient reserves used in germination are concentrated.
Chemical composition of grain
The seeds of grain legumes contain a lot of protein, rich in essential amino acids, minerals and vitamins.
Table. Average chemical composition of grain legume seeds at 14% moisture, in %[1] Fundamentals of agricultural production technology. Farming and plant growing. Ed. by V.S. Niklyaev. - Moscow: "Bylina", 2000. - 555 p. [2]V.V. Kolomeychenko. Crop production/textbook. - Moscow: Agrobiznesentr, 2007. - 600 с. ISBN 978-5-902792-11-6.
| Peas | ||||||
| Forage beans | ||||||
| Lens | ||||||
| Lathyrus | ||||||
| Cicer | ||||||
| Beans | ||||||
| Vigna | ||||||
| Soybean | ||||||
| Lupine narrow-leaved | ||||||
| Lupine yellow | ||||||
| Lupine white | ||||||
| Common vetch | ||||||
| Peanuts |
Soybean and peanut seeds are high in fat.
Nitrogen fixation
Main page: Nitrogen fixation
Nitrogen fixation is a well-known characteristic of legumes. The bacterial species Rhizobium is able to fix atmospheric nitrogen by living symbiotically in root nodules. The bacterial enzyme responsible for nitrogen fixation is nitrogenase; sufficient iron and molybdenum are required for enzymatic activity. The nitrogen fixed in the nodules is used in the growth process and can also enrich the soil after plant death. Under certain conditions, bacteria are capable of releasing soluble nitrogen compounds into the soil.
Rhizobium organisms are free-living and mobile in the soil and, as such, are not capable of fixing atmospheric nitrogen. However, once the bacteria infect plant root hairs, nodules are formed, the bacteria undergo changes and become capable of fixing nitrogen. The relationship between host and organism is specific and if they do not complement each other, the symbiosis will be ineffective or will not develop. The presence of the bacteria and the interaction with the soil environment affect the level of symbiosis. When the desired Rhizobium species is not present in the soil or is present in small amounts, it is sometimes recommended to inoculate seeds with the appropriate strain for the specific crop.
In general, the nitrogen fixed by Rhizobium is not supplied in sufficient quantities to ensure vigorous growth in the early stages of plant growth. This can have a negative effect on yield because N2 fixation requires metabolic inputs, as carbohydrates are used as an energy source for this process. It is questionable to inoculate seeds of crops with short growing seasons with Rhizobium bacteria because of the time required for colonization and nitrogen fixation. In a low intensity production system, the nitrogen supplied by Rhizobium may be sufficient, but not for intensive production. For the latter system, nitrogen fertilizers can be applied.
Growing concern about the environmental and nutritional effects of nitrogen fertilizers has intensified research on the unique nitrogen-fixing capacity of legumes. The transformation of this capacity in non-legume species would be a great boon and a major achievement. At present, due to genetic complexities, it is doubtful that such a transformation will be achieved.
Biological features
Temperature requirements
In general, cultivated legume species have a wide adaptation to temperature. Some species prefer cool and humid conditions, others thrive in hot and dry environments, and many are sensitive to frost.
For grain legumes, higher temperatures during the phases of filling and seed ripening are important, which does not allow sowing at a later date and limits the expansion of cultivation areas to the north.
Table. Air temperature at which grain legumes are damaged in different phases of development, °C (V.N. Stepanov)
| Peas | |||
| Lupine blue | |||
| Forage beans | |||
| Lupine yellow | |||
| Beans |
Table. Temperature requirements of legume crops during different growth periods (V.N. Stepanov)
| Peas | ||||||||
| Lens | ||||||||
| Lathyrus | ||||||||
| Lupine narrow-leaved | ||||||||
| Forage beans | ||||||||
| Cicer | ||||||||
| Soybean | ||||||||
| Beans | ||||||||
Moisture requirements
Grain legumes need more moisture than cereals. They do not tolerate close groundwater. Soybeans, fodder beans, lupines, and peas are the most moisture-demanding. These plants are cultivated in areas with sufficient moisture. Cicer and lathyrus are drought-resistant. Lentils and beans occupy an intermediate position.
Optimal soil moisture for all crops, providing active nitrogen fixation and high yields is moisture from 100% of the smallest moisture capacity to capillary breakdown moisture of about 60% of the smallest moisture capacity.
Nutrient requirements
Since leguminous crops contain a large amount of nutrients per crop unit, the need for elements of mineral nutrition is greater than that of cereals. The need is characterized by removal and maximum consumption.
Table. Nutrient removal and maximum nutrient consumption of 1 ton of seeds and the corresponding amount of organic matter of leguminous crops, kg (G.S. Posypynov, 1983)
| Pea (Pisum sativum) | ||||||||
| Pea (Pisum arvense) | ||||||||
| Cicer | ||||||||
| Forage beans | ||||||||
| Beans | ||||||||
| Lathyrus | ||||||||
| Lentils | ||||||||
| Common vetch | ||||||||
| Lupine narrow-leaved | ||||||||
| Lupine yellow | ||||||||
| Soybean | ||||||||
| On average | ||||||||
The indicators of removal are determined during the harvesting period. The maximum consumption of nutrients and accumulation of organic matter falls on the phase of full filling of the seeds, when the lower beans begin to turn yellow, the upper ones are done, but the leaves have not yet fallen off.
On average, 110 kg of nutrients are removed from 1 ton of grain legume seeds and the corresponding amount of organic matter, which is 2 times higher than from 1 ton of cereal grain. Maximum nitrogen consumption for the formation of 1 ton of legume seeds averaged 69 kg, while for 1 ton of cereal grain – 34 kg. Therefore, when nitrogen fixation activity is low, legume crops reduce yield by 1.5-2 times more than cereals.
In dry summers leguminous crops use less phosphorus than in wet ones and more potassium. When there is a lack of moisture, nitrogen uptake by crops and protein content in seeds is lower than in years with normal moisture supply due to a decrease in nitrogen fixation.
The dynamics of nutrient consumption determines the timing of harvesting legumes for green mass. For example, if peas are harvested at the flowering stage, only one third of the possible crude protein is collected from the crop. It is more rational to harvest this crop when the middle beans are completely done and the filling of the seeds of the upper beans ends. During this period, the largest crop of green mass is formed, the collection of crude protein is greater.
Lupine gives no more than half of the crop in the flowering phase, so harvesting for green mass is not carried out before the phase of shiny beans.
Light requirements
Leguminous crops are divided according to the requirement for light conditions:
- long-day plants, in which the growing season shortens with lengthening daylight hours – peas, lentils, lathyrus, lupines, and beans;
- short-day plants, in which the vegetation period is shortened with decreasing daylight hours – soybeans, mung bean;
- a group of neutral plants – most varieties of common beans, cicer.
Varieties that are neutral to the duration of the day have been developed for almost every crop. For short-day plants, the duration of vegetation increases in the north, for long-day plants – in the south.
Soil requirements
Most cultivated legumes grow best in well-drained, lightly structured, well aerated soils, and suffer from waterlogging. Generally, a soil pH of slightly acidic to nearly neutral is preferable. Optimal for the cultivation of grain legumes are medium-loam, slightly acidic or neutral loamy and sandy loam soils, with high phosphorus, potassium and calcium content.
They do not grow well on acidic and sandy soils, except for yellow lupine which gives good yields on sandy soils with pH 4-4,5. Field peas (Pisum arvense) also give good yields on slightly acidic sandy soils.
Legumes have different requirements for the reaction of soil solution. They are divided into 6 groups according to the activity of symbiotic nitrogen fixation depending on soil acidity.
Table. Classification of legume crops according to symbiosis activity with nodule bacteria depending on soil acidity (pH of salt extract) (G.S. Posypanov, 1983)
| I | Lupine perennial, horned lupine (Lotus corniculatus), yellow lupine, bird's-foot (Ornithopus) | |||||||
| II | Trifolium hybridum, Pisum arvense, Trifolium repens, Lupinus angustifolius | |||||||
| III | Vicia sativa, Trifolium pratense, Pisum sativum, fodder beans | |||||||
| IV | Soybean, white lupine, Vicia villosa | |||||||
| V | Common bean, Lathyrus sativus, cicer | |||||||
| VI | Alfalfa, melilot, sainfoin |
Note. 0 – no symbiosis; 1 – symbiosis very weak, single small nodules on some plants; 2 – symbiosis weak, more than half of plants with nodules, small pale pink nodules; 3 – all plants with nodules, mainly small, pink; 4 – more than half of nodules pink, large; 5 – many large red nodules.
The above classification makes it possible to:
- determine which legume crop is more rational to sow in a particular field with known acidity for the greatest assimilation of atmospheric nitrogen and to produce the greatest yield of good quality;
- at what acidity the chosen crop is able to fix the maximum amount of nitrogen and form the largest yield of good quality;
- to what level of environmental reaction should the soil for the crop be limed to provide the best nitrogen fixation conditions.
Growth phases (phenological phases)
The growth phases of legume crops:
- germination;
- sprouting;
- stem branching;
- budding;
- flowering;
- bean formation;
- ripening;
- full ripeness.
Intensive cultivation technology
Crop rotation
Main article: Leguminous crops of the crop rotation
Leguminous crops can be placed in the rotation after any crops, except perennial leguminous grasses and grain legumes. Placement over legume crops results in the accumulation of specific pests and diseases. Grain legume crops are returned to the former field not earlier than 3-4 years when the number of specific pests and diseases is sufficiently reduced.
Grain legumes are good predecessors for cereals, row crops and industrial crops; their main advantage is nitrogen accumulation as a result of symbiotic nitrogen fixation.
Legumes with a short growing season can be sown for green fodder or hay as fallow-occupied crops, which is especially important for the northern and northwestern areas of the Non-Black Soil Zone, where a short warm period limits the set of fallow-occupied crops.
Fertilizer system
Phosphorus and potassium
The need for phosphorus-potassium fertilizers and application rates for legume crops are determined by the content of these elements in the soil of a particular field. According to the supply of mobile phosphorus (according to Kirsanov) and exchangeable potassium (according to Maslova) soils are divided into 6 groups (All-Russian Institute of Fertilizers and Agro-soil Science, 1982):
- very low supply – less than 2.5 mg/100 g soil P2O5 and less than 4.0 mg/100 g K2O;
- low supply – 2.5-5.0 mg/100 g soil P2O5 and 4.1-8.0 mg/100 g K2O;
- medium supply – 5.1-10.0 mg/100 g soil P2O5 and 8.1-12.0 mg/100 g K2O;
- higher supply – 10.1-15.0 mg/100 g soil P2O5 and 12.1-17.0 mg/100 g K2O;
- high supply – 15.1-25.0 mg/100 g soil P2O5 and 17.1-25.0 mg/100 g K2O;
- very high supply – more than 25.0 mg/100 g soil P2O5 and more than 25.0 mg/100 g K2O.
At very low and low provision of soil with phosphorus and potassium and increased acidity even high doses of phosphorus-potassium fertilizers and lime fertilizers under legume crops does not provide active nitrogen fixation and high yield due to the presence in the arable layer centers of high acidity and low phosphorus, potassium content. On such soils it is better to sow legumes in the second year after liming and fertilizing.
On limed soils with an average supply of mobile phosphorus and exchangeable potassium, the rate of phosphorus-potassium fertilizer is determined on the basis of the biological needs of the culture and the planned yield. Fertilizers are applied in autumn for autumn plowing or in spring for deep cultivation.
On soils with higher and high supply of phosphorus-potassium fertilizers, most often, have little effect on yield. On such soils, you can apply small doses of phosphorus and potassium fertilizers under pre-sowing cultivation to maintain soil security. On soils with a very high supply of fertilizers do not apply.
An exception among grain legumes is yellow lupine. Under it, phosphorus-potassium fertilizer is not applied if the content of phosphorus and potassium is more than 5 mg/100 g of soil.
Microfertilizers
Micronutrient supply strongly affects the activity of symbiotic nitrogen fixation. Soils are classified into 3 groups according to the content of trace elements (All-Russian Institute of Fertilizers and Agrosoil Science, 1982):
- Low supply – less than 0.5 mg/kg soil boron (in water extract), less than 0.3 mg/kg soil molybdenum (in oxalate extract), less than 5 mg/kg soil copper (in 1 n hydrochloric acid extract);
- Medium supply – 0.5-1.0 mg/kg of boron (in aqueous extract), 0.3-0.5 mg/kg of molybdenum (in oxalate extract), 5-7 mg/kg of copper (in 1 n hydrochloric acid extract);
- High supply – more than 1.0 mg/kg of boron (in water extract), more than 0.5 mg/kg of molybdenum (in oxalate extract), more than 7 mg/kg of copper (in 1 n hydrochloric acid extract).
Microfertilizers are applied at low and medium supply.
Bacterial fertilizers
For the formation of nodules on the roots of legume plants, a virulent active bacterial strain of the genus Rhizobium, which according to L.M. Dorosinsky, is divided into 11 species. Each of them infects one or more species of legume plants.
Spontaneous Rhizobium strains are preserved in the soil in the fields where this crop has been cultivated for a long time. For example, nodule bacteria of peas, vetch, and forage beans are almost ubiquitous. Inoculation of seeds of these crops with bacterial fertilizers is most often ineffective. Whereas seeds of lupine and soybean sown for the first time in a given field require artificial infection with appropriate rhizobia strains. In the absence of bacteria, nodules are not formed, nitrogen fixation does not occur, and the crop yield is limited to natural soil fertility.
After liming the soils with high doses of lime fertilizers providing a decrease in the pH of the salt extract by 1.5-2 units, inoculation of all legume crops with active rhizobia strains is carried out, since on acidic soils the strains have reduced activity.
One of the frequently used effective preparations is rhizotorfin, a rhizobia culture derived from sterilized peat.
Treatment of seeds is carried out on the day of sowing or better just before sowing, as the bacteria applied to the surface of the seeds quickly die – already 5-6 hours after treatment their number is reduced by half. If the inoculated seeds were not sown the same day, they are treated again on the day of sowing.
Treatment should be carried out indoors or under a canopy, avoiding direct sunlight, as ultraviolet radiation is destructive to bacteria. For the same reason, sowing is carried out with the seeder boxes closed.
Inoculation is carried out manually or mechanized. When manual treatment, 100-200 kg of seeds are scattered on a tarpaulin and moistened with water with mixing at the rate of 1% by weight of the seeds, powdered with appropriate amount of rhizotorfin and mixed until the preparation is evenly distributed on the surface of the seeds. Using the drug in a suspended form worsens the results.
Mechanized treatment of seeds is carried out by treater machines according to the technology similar to treater treatment. ПУ-15, ПУ-3, ПСШ-3, АС-2, АПЗ-10, ПЗ-10, ПС-10, “Kolos”, “Mobitoks” are suitable for this purpose. Before operation the machine must be cleaned from pesticide residues.
When inoculating and treating seeds with pesticides, consider the following:
- seed dressing with fentiuram, TMTD and similar preparations shall be carried out in advance, at least 1 month before sowing;
- treatment with preparations that are less toxic to nodule bacteria, for example, fundozol, BMK and others based on benomyl, can be combined with rhizotorfin treatment on the day of sowing;
- for better retention of rhizotorfin and protectants on the surface of seeds adhesives are used: bard concentrate (waste from ethanol production) solid or liquid, molasses, flour or starch paste. Doses of adhesive: bard concentrate – 1-1,2 kg, flour or starch paste – 0,5 kg, diluted in 8 liters of water to treat 1 ton of seeds.
Nitrogen
When predicting the provision of legume crops with nitrogen from nitrogen fixation, the compliance of soil acidity with the requirements of the crop, the provision with phosphorus, potassium and trace elements, the presence of spontaneous active strains of nodule bacteria or seed treatment with bacterial fertilizers are taken into account. If these factors are satisfied, you can expect active fixation and high yield of sufficient quality by assimilation of atmospheric nitrogen.
The reliability of the prediction is monitored during the growing season. If 2-3 weeks after sprouting, pink and red nodules were formed on the roots, nitrogen fixation proceeds normally. During flowering and bean formation, when the plants’ need for nitrogen increases, the activity of the symbiotic apparatus should be checked again. By this time, the mass of nodules with light hemoglobin per plant in many crops reaches a maximum. If at this time there are many large red nodules on the roots, the plants are fully supplied with nitrogen. If there are no nodules, they are gray or green, there is no nitrogen fixation.
All legumes make better use of mineral forms of nitrogen than air nitrogen. However, nitrogen fertilizers inhibit nitrogen fixation. Under optimal symbiotic fixation conditions, nitrogen fertilizers are not used. By suppressing symbiosis, they reduce the amount of fixed nitrogen by the amount of assimilated nitrogen fertilizer and do not increase seed production, and high doses of nitrogen fertilizer can lead to its reduction.
On acidic soils where symbiosis is suppressed, mineral nitrogen in the rates of 70-100 kg/ha is applied to obtain a satisfactory yield of peas, fodder beans, narrow-leaved lupine, vetch. In this case it is not possible to obtain a high yield of good quality. Intensification of legume production on such soils consists primarily in liming and creating other favorable conditions for symbiotic activity of nodule bacteria.
Tillage
Main tillage for leguminous crops is similar to tillage for cereal crops. When they are sown after cereals, stubble discing to a depth of 1-8 cm is carried out. In 2 to 3 weeks after discing, autumn plowing on chernozem soils at a depth of 25-27 cm on other soils – to a depth of the arable layer (20-22 cm) using plows with skimmers, such as ПТК-9-35, ПЛП-6-35, ПЛН-4-35.
In case of long warm period after plowing two tillage operations are carried out to destroy weeds by cultivators КПГ-4 or КПС-4.
Presowing tillage includes cultivation, leveling and rolling of soil, for example, with complex units РВК-3, РВК-3,6, РВК-5 or cultivation with harrowing in two tracks at a depth of 8-10 cm by cultivator КПС-4 with harrows БЗСС-1. After cultivation for crops, bringing the seedling to the surface, is carried out packing with ring-spiked rollers СГ-21 or ЗККШ-6. Pre-seeding levelling and rolling allows to provide uniform seeding, uniform emergence of seedlings and plant development, reduce losses at harvesting for seeds of crops with lodging stem.
Preparing seeds for sowing
Seeds of class I and II are used for sowing. 3-4 weeks before sowing, they are treated against root rots and ascochitosis with TMTD at a dose of 3-4 kg/t, with fundozole at 2-3 kg/t, with fenthiuram at 3-4 kg/t. Tachygaren at a dose of 1-2 kg/t is effective against root rot. Treated seeds are treated by machines ПСШ-З, ТСШ-5, ПС-10, “Mobitoks” and АПЗ-10 half-dry with 5 liters of water per 1 ton of seeds. If necessary, seeds are treated with bacterial fertilizers and microfertilizers before sowing.
Timing, sowing methods and seeding rates
The timing, sowing methods and seeding rates are determined by the biological characteristics of the crop and cultivation conditions.
Cold-resistant grain legumes include Pisum arvense, Pisum sativum, and fodder beans. They are sown at the earliest possible time. Delayed sowing of 7-12 days leads to a decrease in their yield by 15-20%.
Warm-loving grain legumes include soybeans and beans. They are sown at a topsoil temperature of 8-12 ° C, usually 10-15 days after the beginning of spring field work.
Seeding rate is determined by location, purpose of cultivation and method of seeding. In areas with sufficient moisture, higher seeding rates are used than in arid areas. With the wide-row method, the rates are less than with the row and narrow-row method, with sowing for green mass, the seeding rate is higher than for seed.
Table. Methods, terms, sowing depth and seeding rates of leguminous crops in the Non-Black Soil Zone[3] Plant breeding/P.P. Vavilov, V.V. Gritsenko, V.S. Kuznetsov et al; Edited by P.P. Vavilov. - M.: Agropromizdat, 1986. - 512 p.: ill. - (Textbook and textbooks for higher education institutions).
| Pisum sativum | Row and narrow-row | Early | ||
| Pisum arvense | Row and narrow-row | Early | ||
| Small-seeded fodder beans | Row (45 cm) and wide-row (60 cm) | Early | ||
| Lathyrus | Row and narrow-row | Early | ||
| Cicer | Row and wide-row (45 cm) | Early | ||
| Coarse-seeded lentils | Row and narrow-row | Following the sowing of peas | ||
| Small-seeded lentils | Row and narrow-row | Following the sowing of peas | ||
| Vicia sativa | Row and narrow-row | Following the sowing of peas | ||
| Lupinus angustifolius | Row and narrow-row | Following the sowing of peas | ||
| Lupine yellow | Row | Following the sowing of peas | ||
| Lupine white | Row and wide-row (45 cm) | After sowing early crops | ||
| Soybean | Wide-row (45, 60 cm) | At a soil temperature of 8-10 °C | ||
| Common bean | Wide-row (45, 60 cm) | At a soil temperature of 10-12 °C |
Crop care
Crop care includes loosening and destruction of soil crust, weed, pest and disease control. Methods are specific for different legumes.
Harvesting
Because of the uneven maturity of the seeds, most legumes are harvested in two phases. First, they are mowed in swaths, and when the mass dries up, they are threshed by combine harvesters adjusted for threshing legume crops. Cicer and soybeans are harvested by direct combining.
Postharvest handling of seeds
After harvesting, seeds are immediately passed through preliminary cleaning machines such as ОВП-20А, ЗАВ-10, ЗАВ-20, К-527. When the moisture content of the seeds less than 17% continue further cleaning and sorting on machines ОС-4,5, СМ-4, К-523 or on grain cleaning complexes ЗАВ, КЗС with additions СПЛ-5 and СП-10.
At humidity over 17% after pre-cleaning they are dried on dryers active ventilation in the unit with air heaters such as ВПТ-400, ВПТ-600, ТАУ-075, ТАУ-1.5 or dryers mine type. During drying, the following regimes are observed:
- at moisture content of seeds before drying more than 27% – the temperature of the coolant 25 °C;
- at the humidity of 21-27% – the temperature is 28 °C;
- at the humidity of 18-21% – the temperature is 32 °C;
- when the humidity is less than 18% – the temperature is 40 °C.
Mound height should be no more than 50-70 cm. Air flow rate in 1 hour – 1000-1500 m3/t of seeds. Duration of drying at the specified modes of 2-3 days.
Of the mine type dryers used СЗШ-8, СЗШ-16, СЗШ-16Р, Т-662 (GDR), М-819 (Poland).
If capacity of drying units is not enough for the entire batch of wet grain, the excess is placed for temporary storage in floor units or bins of active ventilating БВ-25, БВ-40.
Seeds, dried to condition moisture 13-16% depending on the culture, cleaned and sorted, stored in dry ventilated rooms with a bulk height not exceeding 2.5 m or in bags up to 8 rows high and width not exceeding the length of two bags.
Cultivation for green mass
The maximum yield of green mass of legumes of high quality with the lowest cost is obtained in the cultivation of perennial leguminous grasses in pure crops. However, due to the limited number of such crops, annual legumes are grown to produce green mass used for the production of grass meal, haylage, as animal feed in the summer. Seeds of field peas (Pisum arvense), narrow-leaved lupine (Lupinus angustifolius), vetch (Vicia sativa) and mossy vetch (Vícia villosa) are almost not used in the feed industry, they are grown mainly for green mass. Typical grain crops such as peas (Pisum sativum), fodder beans, lathyrus, soybean, white lupine are also cultivated for green mass.
The agrotechnics of legume crops cultivation for green mass is basically similar to the agrotechnics of cultivation for seeds. Only the rate of seed sowing is increased by 10-15%.
Harvesting for green mass is carried out during the period of complete filling of seeds in the middle beans, when the lower beans begin to turn yellow or brown, the upper beans finish the filling of seeds, and the plants have not yet dropped leaves. When harvested at the flowering stage, most crops accumulate only 30-40% of the maximum possible protein.
Table. Comparative productivity of grain legume crops at harvesting for green mass in different phases of vegetation, 100 kg/ha (G.S. Posypanov, 1982)
| Pisum arvense | |||||||
| Vetch | |||||||
| Lathyrus | |||||||
| Pisum sativum | |||||||
When there is a need for early harvesting for green mass in the farm it is advisable to sow several types of leguminous crops with different timing of crop formation. The simultaneous onset of the phases of flowering and seed ripening will extend the harvesting of green matter by 40 days with a minimum yield shortfall.
Mixed crops of leguminous crops
Cultivation of cereal crops such as oats, winter rye, corn, and sorghum for green mass is common in farm practice. However, cereal-based feeds contain little protein. For example, green mass of oats contains 2 times less protein than green mass of vetch, the content of digestible protein in the green mass of corn is 2.5 times less than in pea, 3 times less than in soybean, and 3.5 times less than in Lathyrus sativus.
Table. Protein content in green mass of fodder crops and its digestibility, % (M.F. Tomme et al., 1970)
| Lathyrus sativus | |||||
| Soybean | |||||
| Lupinus albus | |||||
| Lupinus luteus | |||||
| Vicia sativa | |||||
| Pisum sativum | |||||
| Vicia villosa | |||||
| Pisum arvense | |||||
| Forage beans | |||||
| Lupinus angustifolius | |||||
| Winter rye (beginning of earing) | |||||
| Oats | |||||
| Sorghum | |||||
| Sunflower | |||||
| Corn (milky ripeness) | |||||
| Vicia + oats | |||||
| Soybean + corn | |||||
| Lathyrus + oats | |||||
| Peas + oats | |||||
| Winter vetch + rye | |||||
| Peas + corn | |||||
Growing legumes in mixed crops with cereal crops increases the amount of protein in the green mass, digestibility and digestibility of cereal protein. For example, green mass of oats contains 7.8% of digestible protein, while the mixture of oats and vetch contains 1.6 times more. Adding soybeans to corn crops increases the content of digestible protein by 2.3 times.
Protein content of legume-grass mixtures is determined by the ratio of components. For example, if the proportion of vetch in a vetch-oat mixture is 55-60% and oats 40-45% by mass, the digestible protein content of the mixture reaches 14%, and if vetch in the mixture is only 20-30%, the protein content of the mixture does not exceed 9%.
Plant protection system
Pests and diseases of peas and beans can reduce yields, ruin quality, jeopardize production reliability, and disrupt the throughput of packing and processing plants. Very rarely are dramatic losses caused by disease infestations of epidemic proportions or an unusually severe infestation of a particular pest. Both are often related to climatic conditions. There are less serious losses, such as when patches of diseased plants appear, or when the pest infestation is not very severe, and there are subtle and often inconspicuous losses, which can result from the gradual accumulation of a pest or soil-borne pathogen, but which gradually reduces viability and profitability.
Control methods now increasingly rely on management and prevention measures rather than a direct treatment approach when symptoms or pests appear. Relying on synthetic pesticides is discouraged, and increasing emphasis is being placed on prediction, prediction, and monitoring as a means of providing an avoidance strategy or a managed approach by determining the best time to apply pesticides and justifying their use. In many crop-processing countries, much emphasis is placed on the need to track crops from field to plant, where each contribution-agronomic, plant nutrition, and pesticide application-is recorded by the grower, and these records remain available for inspection for some time after harvest.
The assured produce scheme, known as Red Tractor, has been in effect in the UK for several years as a voluntary standard set by the food industry, and a similar scheme is used in Europe (GLOBALG.A.P.). Both schemes include harvest protocols that are standardized in consultation with retailers, food processors and merchants to ensure transparency and food safety for the consumer.
In previous decades, many broad-spectrum pesticides were introduced that were later found to have negative effects on the environment and non-target organisms. The fate of these old pesticides in soil or water involves the accumulation of residues that take many years to decompose.
Recent legislation has led to the withdrawal of many active ingredients that pose a risk to the environment or the operator, and the introduction of new generation pesticides is now only possible after rigorous testing by manufacturers. Even then, new research can often uncover unexpected problems that may be related to the pesticide or its by-products.
Pesticides are now being used less and less frequently, especially in Europe and increasingly in other countries, because pressure from the retail trade requires quality assurance from crop producers for human consumption, involving full transparency and justification of all measures, including the use of pesticides on crops.
Thus, pest and disease management has moved to an integrated approach that uses any practical methods of predicting, predicting or monitoring before decisions are made to apply or not apply pesticides. This includes all aspects of farming from the use of healthy seeds, choice of field, variety and crop rotation, frequent crop monitoring with monitoring systems if available, and a detailed understanding of the crop and pest or pathogen biology.
Peas and beans (Vicia and Phaseolus species) can be affected by a wide range of pests and diseases, and because these crops are grown in many regions of the world. More comprehensive lists along with illustrations of pests and their damage as well as disease symptoms can be found in a number of publications (Allen and Lennie, 1985; Kraft and Pfleger, 2001; Schwartz et al., 2005; Biddle and Cattlin, 2007).
Because all of the crop species described are legumes, they can be hosts of the same organism even with minor differences in race or strain, especially in the case of fungal pathogens, and so where there are commonalities, they are identified. In each case, symptoms, effects on crops, pest or disease biology, monitoring methods, and economic thresholds to justify treatment are described.
Disease control preparations
Fusarium root rot in pea – Phytosporin-M (titer not less than 2 billion living cells and spores/g Bacllus subtilis, strain 26D), application rate – 10 l/t for pre-sowing treatment of seeds.
Pea rust and powdery mildew – Alto (e.g. ciproconazole, 400 g/l), application form – spraying during vegetation.
Ascochytosis, rust, powdery mildew, chocolate leaf spot – Rex Duo (a.s. thiophanamethyl, 310 g/l and epoxiconazole, 187 g/l), application form – spraying during vegetation.
Vegetable legumes
In terms of volume and caloric value, the value of grain legumes is superior to that of vegetable legumes. Nevertheless, the nutritional value of the latter is very significant. Vegetable legumes, in addition to their fresh use of pods, leaves, tender shoots and hoarding roots, also produce a wide range of dried seeds. Some species are widely used as forage, cover crops and green fertilizers, food oils, as well as wood, dyes, gum, and many other industrial products.
A list of vegetable legume crops:
- Apios americana (Apios) fresh and dried mature seeds, tubers, and rhizomes are used as food;
- Arachis hypogaea (Arachis peanut) – dried mature seeds, tender shoots and leaves, oil;
- Canavalia ensiformis (Jack bean) – dry mature seeds and immature pods;
- Canavalia gladiata (Sword bean) – dry mature seeds and immature pods;
- Cajanus cajan (Pigeon pea) – fresh and dried mature seeds, immature pods;
- Cicer arietinum (Chick pea) – fresh and dried mature seeds, immature pods;
- Cyamopsis tetragonolobus (Cluster bean) – immature pods;
- Dolichos lignosa (Australian pea) – dried mature seeds;
- Glycine max (Soybean) – immature seeds, mature fresh and dry seeds, immature pods, germinated seeds, oil and other food forms;
- Lablab purpureus (Hyacinth bean) – fresh and dry mature and germinated seeds;
- Lathy rus sativus (Grass pea) – fresh and dried mature seeds and tender leaves;
- Lens culinaris (Lentil) – mature dry seeds and immature pods;
- Lupinus spp. (Lupines) – mature dry seeds;
- Pachyrhizus ahipa (Ahipa) – tuberous roots;
- Pachyrhizus erosus (Yam bean) – immature beans (pods), tuberous roots, starch;
- Pachyrhizus tuberosus (Potato bean) – tuberous roots;
- Phaseolus acutifolius (Tapary bean) – mature dry seeds;
- Phaseolus coccineus (Scarlet runner bean) – fresh and dry mature seeds, immature beans, tuberous roots, flowers;
- Phaseolus lunatus (Lima bean) – immature, fresh and dry mature seeds, immature beans, tender shoots and leaves;
- Phaseolus vulgaris (Snap and common bean) – fresh and dry mature seeds, immature beans, tender shoots and leaves;
- Pisum sativum (Garden and field pea) – immature, fresh and dry mature, germinated seeds, immature beans, tender shoots and leaves;
- Psophocarpus tetragonolobus (Winged bean) – immature, fresh and dry mature, sprouted seeds, immature beans, tender shoots and leaves, tuberous roots;
- Pueraria lobata (Kudzu) – starch or oil;
- Sphenostylis stenocarpa (African yam bean) – tuberous roots;
- Trigonella foenum-graecum (Fenugreek) – dry mature seeds, tender shoots and leaves;
- Tylosema esculentum (Marama bean) – dry mature seeds and tuberous roots;
- Vicia faba (Broad bean) – fresh and dry mature seeds;
- Vigna aconitifolia (Mat bean) – dry mature seeds and immature beans;
- Vigna angularis (Adzuki bean) – dry mature and germinated seeds, immature beans;
- Vigna mungo (Urd bean) – dry mature seeds and immature beans;
- Vigna radiata (Mung bean) – dry mature and germinated seeds, immature beans;
- Vigna subterranea (Bambara groundnut) – immature and dry mature seeds;
- Vigna umbellata (Rice bean) – dry mature seeds and immature beans;
- Vigna unguiculata cultural group cylindrica (Catjang cowpea) – fresh and dry mature seeds, immature beans, tender leaves;
- Vigna unguiculata cultigroup sesquipedalis (Yardlong bean) – immature beans;
- Vigna unguiculata cultigroup unguiculata (Cowpea) – fresh and dried mature seeds, immature beans, tender sprouts and leaves.
Some vegetable legumes contain toxic substances such as saponins, latrogens, cyanogenic and other glycosides, protease and amylase inhibitors, and hemagglutinins. Some legumes grown on soils high in selenium or molybdenum can absorb excessive amounts of these elements, which can be toxic when consumed.
Canavalia ensiformis (L.) DC., Jackbean, horsebean.
Canavalia mead is native to Central America and the West Indies, where a wide variety of plant types are found. Tender young pods and immature seeds are used for vegetables; the plants are also used as fodder or green fertilizer.
A hardy and bushy upright annual plant over 1 m tall, deeply rooted and drought tolerant. Flowers are self-pollinated, pink to purple. Suspended pods are large, 20-30 cm long and 2-2.5 cm wide, containing 8-20 slightly flattened white seeds, which should be cleaned by boiling and washing before use. The carbohydrate content of the dry seeds is about 55% and the protein content about 24%. Immature fresh pods contain about 13% carbohydrates and about 7% protein.
Canavalia peaked (Canavalia gladiata (Jacq.) DC), English Swordbean, comes from the Old World and probably from C. virosa, which is found wild in tropical Asia and Africa.
The young pods and seeds of Kavalia piqua are a commonly used vegetable in the tropics, especially in Asia. Although widely cultivated, production is mostly limited to home gardens and local markets.
Although C. gladiata is grown as an annual, it differs from C. ensiformis in that it is a perennial and climbing plant. The flowers, mostly self-pollinated, are pinkish white or white. The pod length to width ratio is used to identify C. gladiata from C. ensiformis; the pod length to width ratio of C. gladiata is less than that of C. ensiformis. The name Swordbean (from “sword bean”) probably derived from the appearance of hanging pods 15-40 cm long and 4-5 cm wide, usually containing 5-10 dark red seeds with a thick, tough seed coat. Although rare, white seeds are preferred because of their flavor. The seeds are relatively large but variable, and the weight of individual seeds may vary from 1 to 4 g. Another distinguishing characteristic is the scar on the seed mound, which in the sword bean is more than half the length of the seed, while in the jack bean the scar is less than half the length of the seed.
For optimal growth and yield, sword bean plants need a tropical climate with average temperatures between 20°C and 30°C. Because the roots penetrate deep into the soil, the plants are drought-resistant. The plants can be grown in nutrient-poor soils, can tolerate some salinity, and even tolerate some shade.
Seeds are used for propagation with a spacing of usually 50-60 cm between plants in rows spaced 75-90 cm apart. Germination and early growth is usually rapid; ideally, the plants should be provided with some support. After 3-4 months, harvest green pods about 10-15 cm long before the seeds swell. Yields can reach 4 tons per hectare. It takes five to 10 months of growth to harvest fully mature seeds; yields of mature seeds are 700 to 900 kg/ha.
The young green pods are used as cooked vegetables; the seeds, while still juicy, are also eaten. Sometimes the flowers and young leaves are used as a decoction. Mature seeds, as with jack beans, need to be processed before eating to remove toxic substances that can interfere with the body’s ability to absorb nutrients. This inconvenience tends to limit the use and popularity of sword beans.
Pigeon pea (Cajanus cajan)
Pigeon pea (Cajanus cajan (L.) Huth. C. indicus), red gram, Congo pea.
On the basis of findings of wild species, the origin of pigeon pea is attributed to Africa. However, this is doubtful, since the variability found in India clearly makes it a center of diversity and possibly of origin. Pigeon pea is a crop of great importance in India, where its production occupies a vast area of arable land. Its importance is also great in other Asian countries.
Pigeon pea ranks sixth in the world production of dry legume seeds. The wide climatic and soil adaptability of pigeon pea is the reason for its wide use. The deep root system increases drought tolerance. Plants are intolerant of waterlogging or shade.
Plants grow 1 to 4 m tall, are somewhat woody, and although short-lived perennials, are usually grown as annuals. When used for forage, the crop can last for 3 to 4 years. The lanceolate leaves are 5-10 cm long. Pigeon peas are usually propagated by seed, but stem cuttings can also be used.
Flowers are yellow-orange in most varieties, red or purple in others. Most varieties are short-day, but some dwarf forms are virtually photoperiod insensitive. Flowering is indeterminate, and the flowers are self-fertile, but insect visitation can result in considerable cross-pollination.
The pods form within 3-4 months after sowing and are usually flat and wide, 4-10 cm long and 1-3 cm wide, containing round or oval seeds. The color of the seeds varies from variety to variety. Seeds take six months or more to mature in early varieties and 9-12 months in late varieties.
Two botanical varieties are recognized: C. cajan var. indicus, known as “tour”, which is a low-growing, early maturing plant with green pods usually containing three seeds. Another variety, C. cajan var. bicolor, known as “arhar,” is a large, bushy, late maturing plant with dark colored pods containing 4-5 seeds.
For vegetable purposes, the immature seeds are used fresh, but significant quantities are processed through canning. Fresh green pods are also consumed in large quantities. In general, pigeon peas are of primary importance as a legume crop, mainly for making dal. Dry seeds contain about 57% carbohydrates and 19% protein, while for juicy seeds these figures are 20% and 7% respectively.
Guar (Cyamopsis tetragonolobus)
Guar (Cyamopsis tetragonolobus (L.) Taub. C. psoralioides), English Cluster bean.
The origin of the guar is not entirely clear, since no wild species has been found. The species probably originated in Africa and was domesticated in the arid regions of western Asia after it was introduced by Arab traders. The crop is widely cultivated in India, Pakistan, and Myanmar for vegetable and industrial purposes.
The plants are upright and bushy, often reaching a height of 3 m, but dwarf forms are also found. Being drought-tolerant, the crop is well suited to growing on dry land, but is sensitive to flooding. It has better salinity tolerance than many other legumes.
The self-pollinated flowers of this short-day annual are white or pinkish-white at first, then change to blue.
The pods, compressed and clustered like many stiff and straight fingers, are 4 to 10 cm long and contain 2 to 10 seeds, each about 5 mm in diameter. Cultivars grown to produce pods usually contain fewer seeds.
Propagation takes place by seeds, usually scattered. When growing in rows, the distance between plants is about 15 cm per row and 60 cm between rows. Vegetable pods are usually harvested 3-4 months after planting; mature dry seeds are harvested 5-7 months later. Dried seeds are rarely used as human food, but are widely used as animal feed and industrial products. The mucilaginous gum galactomannan contained in the endosperm of the seeds is used in textile and paper production and other applications. The carbohydrate content of the dried seeds is 40% to 45% and the protein content is 30% to 33%.
Lablab purpureus
Lablab purpureus (L.), syn. Dolichos lablab, D. nigar, Lablab vulgaris), Hyacinth bean (“hyacinth bean”), Indian bean, Egyptian bean.
The probable origin of the lobia is India, where wild forms are still found, and where the crop has been cultivated since ancient times. However, others, including Vavilov, have suggested that the species was introduced to Asia from Africa. Immature pods and tender seeds are a popular vegetable in India and many tropical regions. The dried mature seeds are also an important food item, as are the germinated seeds. The large starchy root can be eaten and the plants are sometimes used as ornamental plants.
The plant is a perennial, but is mostly grown as an annual to produce long, edible pods. Plants grow well from sea level to high altitude (2200 m), in regions with low rainfall and high temperatures, and are intolerant of waterlogging. Although dwarf varieties are grown, typical hyacinth bean plants have a climbing type of growth, with vines 6-10 m long when maintained.
The trifoliate leaves are large (15 cm), almost diamond-shaped, and contribute a large biomass.
Cultivars vary in their response to photoperiod; there are both long-day and short-day forms. Cultivars also exhibit wide variations in stem, flower, and seed color.
Flowers are white, pink or purple, mostly self-pollinated. Green or purple The pods are thin, flat, oblong, often curved. Harvesting occurs when the pods are 5 to 10 cm long and before the seeds mature. The pods contain three to six small, round seeds that fully mature in 3 to 5 months.
The color of the seeds is usually white or black, but reddish-brown and mottled seeds are found. They all have a prominent long white tubercle. The white seeds contain small and non-toxic amounts of cyanogenic glucoside and trypsin inhibitor, while the dark varieties contain large amounts of both.
Lobia is often sown together with sorghum or corn. This combination is beneficial because most of the growth of the bean crop occurs after the companion crop is harvested, and the sorghum or corn stems help support the vines. For fresh pods, plants are often planted on a hill to group two or three plants at equal distances of about 100 cm. The plants are supported to make it easier to harvest multiple harvests. This crop is usually grown for the pods, but when growing for mature seeds, a wide-row planting is often used. In row planting, the distance between plants is usually 10-15 cm in a row and 50 cm between rows.
Fresh pods are cooked and eaten like string beans. They contain about 4-5% protein. Dried seeds contain 50% to 60% carbohydrates and 20-25% protein.
Australian peas (Dolichos lignosus)
The Australian pea, Dolichos lignosus, has a bushy (1 m tall) type of growth. The plants are perennials, but are also cultivated as annuals. D. lignosus differs from D. lablab in that its leaves and unpalatable pods are much smaller. Besides these phenotypic differences, the crop shares many features in development and growth. The related Dolichos uniflorus, known as horse gram, is a hardy, semi-erect, annual plant grown as a legume crop.
Hicama (Pachyrhizus erosus)
Hickama, or Pachyrhizus erosus (L.) Urbanu.
Other names: yam bean and jicama (English), Sincamas or sinkamas (Philippines), Fan-ko and sar-gott (China), Dolique bulbeus (French).
Hickama is a perennial plant native to a wide region of tropical America, from Mexico to northern South America. It is widely cultivated for its tuberous roots in these regions, as well as in areas of the Philippines and southern China with similar growing conditions.
Close cultivated species are P. ahipa (domesticated in Bolivia and northern Argentina) and P. tuberosus (domesticated in the upper Amazon River). Wild forms of chicama are found in Mexico and northern Central America; two recognized wild species are P. panamensis and P. ferrugineus. The common name “jicama” is the Spanish form of the Nahuatl Indian word “xicamatl.
Hicama plants grow well in hot, humid environments and require a long, warm, frost-free growing season. Wet, light, well-drained soil and a short day are preferred for optimal production of fleshy tuberous roots.
Hickama is a climbing plant with long vines 3 or 4 m long, sometimes longer. Its leaves are entire or lobed, diamond-shaped, about 15 cm long. With the onset of a short day, flowering begins, new vegetative growth is reduced, and growth of the storing roots is accelerated. During long days, although storing roots may occur, vine growth strongly competes with root growth. It is common for flower growers to remove the blossoms because pod filling is a strong absorber and competes with root buildup.
Purple or white flowers develop in upright inflorescences, forming pods 7-14 cm long and 1-2 cm wide. Although the immature pods are edible when cooked, the mature pods, leaves and seeds are poisonous. The seeds are somewhat flattened, mostly rounded, 5-10 mm wide, and unlike other Pachyrhizus species, they are never kidney-shaped. It usually takes 10 months to produce mature seeds. Varieties with greenish-brown seeds are preferred because they are more productive than varieties with green or brown seeds.
The preferred shape of the tuber root is a flattened ball like a turnip, although elongated, spindle-shaped roots are also found. The outer skin is brown to light brown in color. The inner flesh is white, not discolored by irradiation, has a watery, crisp texture and a sweet taste comparable to Chinese water chestnut. The best quality rootstocks are usually 10 to 15 cm in diameter and weigh about 2 kg, although some reach 30 cm in width and weigh more than 3 kg. Roots that are too large usually become fibrous and starchy to the detriment of crispness and sweetness. There are two main species grown in Mexico. The “jicama de leche” variety has a dark skin, thin spindly root, not very juicy, with a milky flavor. Jicama de agua has a light skin, turnip-shaped, very juicy root, with a sweet, watery flavor.
Propagated almost exclusively by seeds (about five seeds weighing 1 g), which are planted 2-4 cm deep. Germination usually occurs within 6-12 days. Plants often develop a strong symbiosis with Rhizobium bacteria. Root shoots are sometimes used for clonal propagation. Plants are planted in rows and are often grown as hill crops. Row spacing varies from 15 to 30 cm and 100 cm between rows; lower planting densities are used in hill planting or intercropping. Plants with stakes or trellises are more productive than those without support.
Root crops are harvested by hand digging or after plowing. Although yields can vary from 4 to more than 45 tons/ha, typical yields are about 15 tons/ha. Depending on growing conditions, it takes 4 to 8 months to produce marketable-sized root crops. They are usually cleaned of soil and washed before sale.
Root crops can be stored in the field and harvested as needed. An interesting procedure used by some growers, especially for field storage, is to leave the root crops unhumidified for several weeks before harvesting, which causes some shrinkage. A few days before harvest, the field is irrigated and the stored roots easily absorb moisture and regain their turgor and weight.
After harvest, the tuber-like root skin thickens and limits moisture loss. Roots for storage can be stored for more than a month at 13-15°C; but if left for a long time at temperatures less than 12.5°C, cooling damage can occur. Temperatures above 15°C help to reduce the incidence of mold.
Yam beans are usually eaten raw in vegetable and fruit salads and are appreciated for their mild flavor and juicy crunchy texture; they are often consumed as a snack. The texture also remains crispy after boiling or pickling. Yams beans are low in calories; carbohydrates are less than 10% and proteins are just over 1% of fresh weight. Rotenone, found in mature pods and seeds, has insecticidal properties. The irritating hairs of the leaves contain pachyrhizide, a poisonous glycoside.
Winged beans (Psophocarpus tetragonolobus)
Winged beans, Psophocarpus tetragonolobus (L.) DC. (syn. Tetragonolobus purpureus). Other names: Goa bean, tetrahedral bean, Manila bean, kok-tau.
Winged beans were once considered a miracle plant because the pods, seeds, flowers, stems, tuberous roots and leaves are edible and nutritious; even the oil from the seeds has high nutritional value. It is reported to have similar nutritional properties to soybeans. Nevertheless, extensive cultivation on large farms has not materialized. However, winged beans are an excellent vegetable for the garden and are widely used as a semi-domesticated subsistence crop in Southeast Asia and especially in Papua New Guinea.
The coastal region of East Africa is assumed as the center of origin, but it is possible that the winged bean has a tropical Asian origin. Interestingly, it is not a major crop in Africa. The species is well distributed in South and Southeast Asia and on many Pacific islands. A large variety is found in Papua New Guinea.
Although winged beans are a fast-growing perennial with vines up to 2-4 m long, the crop is usually grown as an annual. The three-lobed leaves are broadly ovate, and the numerous shallow roots have long lateral outgrowths. As a tropical plant with a good subtropical adaptation, winged beans are well adapted to humid conditions. Days with temperatures of 30°C and nights with temperatures of 22°C are most favorable for vegetative growth. Daytime temperatures of 24°C and nights of 13°C are favorable for root growth. The plant is characterized by the presence of numerous root nodules and thus can utilize bacterial fixed nitrogen. Plants can be relatively productive when grown in low fertility soils, but yields increase with supplemental nutrition. Winged beans are very sensitive to waterlogging.
Propagated usually by seed but stem cuttings may be used. Sprouts appear after 5-7 days at 25°C, which is the optimum average temperature for growth. The spacing between plants depends on the variety. Winged beans require support to produce pods, and in most cases the distance between plants is on average 20 cm, and 90 cm between rows. Winged beans are often planted with other crops. When growing for tuberous root crops, the plants are usually not pinned and can exceed 200,000/ha. Supporting does not affect root crop yields, but it does push back the peak pod production period by 1 month. Although the tuberous roots take about 8 months to reach a diameter of 3-4 cm. The pods can develop in as little as 3 months, which is about 1 month after flowering; the seeds mature in 5 months.
Most varieties are short-day plants with indeterminate flowering times; there are varieties that are almost day-neutral. Breeding efforts are aimed at increasing photoperiod sensitivity, determinate flowering, and dwarfing of plants. The self-pollinated flowers are white, pale blue or purple. Pods are often the primary target of production, but growers usually cut back flower buds and young shoots to increase the root system. The pods come in all shades of green, and some are purple in color. They are all tetrahedral, with jagged, thin, winged edges across the length of the pod. The pod varies in length from 5 to 35 cm and in width from 2 to 5 cm. Overdevelopment of the pods quickly develops fiber; dried pods tend to crumble. The number of seeds in a pod can vary from 5 to 20. The seeds are almost round, the largest being about 1 cm in diameter; the average weight of a seed is about 250 mg. The color of the seeds is usually white or black, but yellow and brown seeds are also found.
Yields of fresh pods are 10-15 t/ha, and up to 30 t/ha in experimental plantings. Tuber root yields are 5 to 10 t/ha and seed yields are 1 to 1.5 t/ha. The protein content of immature fresh pods is 1% to 3%, while the fresh leaves have 5% to 7% protein and high levels of provitamin A and vitamin C. Fresh tuberous roots, which are the preferred product in Papua New Guinea, contain 8-10% protein. The protein content of the dry seeds is about 33%, and the carbohydrate and oil content is 32% and 16%, respectively. Fresh pods have a short shelf life and usually do not store, while the roots can be stored for up to 2 months if necessary.
Fenugreek (Trigonella foenum-graceum)
Fenugreek, Trigonella foenum-graceum L. Other names: fenugrec, metha.
Endemic to the Mediterranean region, fenugreek is an annual herb grown for centuries in the Middle East and India as a food and as a forage crop and green fertilizer. In India, the young leaves are used as fresh herbs and also dried in the sun for later use.
Plants grow to a height of 40-90 cm. The white flowers bloom 50-80 days after planting and produce long, slender pods 8-15 cm long. The pods contain 10-20 seeds which take 180-210 days to mature. The mature seeds have a pungent taste and are used to make curry powder and other seasonings. The seeds contain about 25% protein and 50% carbohydrates and are said to have medicinal properties.
Maram bean (Tylosema esculentum)
Maram bean, Tylosema esculentum (syn. Bauhinia esculentum), is a perennial, drought-resistant plant native to southern Africa.
The plant is cultivated and also harvested from the wild for its seeds, which are comparable to soybeans in protein content and quality, and to peanuts in oil content. Edible tuberous roots are also produced.
Sprawling vines grow up to 4-6 m in length and need a trellis. The leaves are bilobate, 8-15 cm wide. The yellow flowers form clusters of three to nine. The pods are flat and oblong, about 6 cm long, dark brown when mature. Each pod usually contains two flat, oblong seeds, each about 2 cm long.
After several years of growth, tuberous roots can weigh more than 10 kg; plants that have yielded roots weighing more than 100 kg have been reported. However, young, small, tender roots weighing 1-2 kg are usually roasted, boiled, or fried. The seeds are usually roasted, but also boiled. Because they contain a strong trypsin inhibitor, they should not be consumed without boiling.
Moth bean (Vigna aconitifolia)
Moth bean, Vigna aconitifolia (Jacq.) Marechai (syn. Phaseolus aconitifolius), English moth/mat bean, native to India, Pakistan and Myanmar (Burma), where it is found in arid and semi-arid areas from sea level to heights above 1000 m, but not adapted to humid tropics. A short-day, hot-weather, drought-resistant plant, it is a well-branched annual with a short ground-trunked trailing habit of growth.
The small yellow self-fertile flowers form pods 5-6 cm long and 5 mm thick, containing six to nine small (5 mm) yellow to dark brown rounded seeds, similar to Riesling. The crop matures in 2-3 months and is often sown with grains.
Moth beans are a popular crop in India, where the green immature pods are used as vegetables; the mature seeds, which contain about 60% carbohydrates and 23% protein, have many food uses.
Adzuki (Vigna angularis)
Adzuki, Vigna angularis (Willd.) Ohwi & Ohashi (syn. Phaseolus angularis), English adzuki bean.
The origin of adzuki is unclear; some researchers consider the Indo-Burma-China region the center of origin, with diversity associated with domestication in regions of south-central China, Japan, China, Korea, and India. The use of adzuki has been found to have occurred as early as 1000 B.C. in Korea; it is believed to have originated even earlier in China. According to one hypothesis, adzuki was domesticated from wild forms; another hypothesis is that it came from the rice bean, Vigna umbellata. Adzuki means “little bean,” and when translated from Japanese to English, adzuki is spelled azuki. Adzuki remains an important legume crop in these Asian countries. China is the leading producer, followed by Japan, the Korean Peninsula and Taiwan with 670,000, 120,000, 30,000 and 20,000 hectares planted respectively.
Adzuki is a short-day annual best adapted to growing in areas between 35 and 49° latitude. Wet and warm or high growing temperatures of 25°C to 30°C are most favorable for high seed yields; dry air at harvest may increase the likelihood of seed shedding. Many varieties are land varieties that vary in the degree of determinacy of growth. Early-ripening varieties are highly determinate, while later-ripening varieties are less determinate. Most varieties are bushy, about 70-75 cm tall, with upright, pea-like foliage; some varieties are grape-like and have a prostrate type of growth. They are tolerant of drought but, being intolerant of waterlogged soils, require good drainage.
Adzuki plants are propagated by seed, and planting densities vary greatly from different growers, ranging from 150,000 to more than 300,000 plants per hectare. Planting is done both by spreading and in rows. Seeds are sown to a depth of 2-5 cm, at a distance of 8-10 cm from each other in rows, the distance between which varies from 20 to 60 cm.
The bright yellow flowers are self-pollinated, although cross-pollination occurs. The mature, cylindrical, mung bean-like pods are 6-12 cm long and about 0.5 cm wide, usually containing up to 10 oblong red seeds; other seed colors include black, green, gray, yellow, white, and mottled combinations of these colors; red or maroon is preferred. The seed shape is usually sub-cylindrical with truncated ends, with a projecting ridge on the side of the tubercle, and varies in length from 5 to 10 mm. Cultivars that produce large seeds are known as “dyna gon.” The seeds mature about 40-50 days after oviposition.
Seeds are usually harvested after 90-140 days of growth, but depending on the variety and growing season, this can be as long as 160 days. Immature pods are used like fresh beans, but they are relatively fibrous. Sprouted seeds are also used for vegetables. Dried seeds contain about 60% carbohydrates, 20% protein and a small 1% lipids. In Japan and other Asian countries, dried adzuki beans are used as “an”, a red, sometimes white, pasty product consisting of a cooked mashed adzuki bean and sugar. It is widely used in baked goods and confectionery, and as a filling for desserts and ice cream. Boiled beans are also a common ingredient in rice dishes (seki han) and soups. A mixture of adzuki and wheat flour is used to make noodles.
Urd (Vigna mungo)
Urd, Vigna mungo (L.) Hepper (syn. Phaseolus mungo), English urd bean, black gram.
Although the cultivation of urd in India is ancient, the wild form is unknown. The plant is a semi-erect annual, well branched but less than 1 m in height. The stems are covered with long, dense, brown hairs. Flowers are self-pollinating, pale yellow in color. The hairy pods, which mature about 20 days after flowering begins, are relatively short (4-7 cm) and thin (0.5 cm). They contain 6-10 small, usually black, oblong seeds. Of the two main varieties, one is early maturing with large black seeds and the other is late maturing with small olive-green seeds. The carbohydrate content of the dry seeds is about 57% and the protein content is about 23%.
Urd is an important grain staple crop in India, but differs from mung bean (Vigna radiata, mung bean) in that it has varieties with a black seed coat. The plants have a wide adaptation to drought, soil, and temperature. The green pods are used as a vegetable, but the main use is for dried seeds for making dal and flour. Cultivated on millions of hectares, this crop is an important staple food because it contains dietary protein.
Mung bean (Vigna radiata)
Mung bean, Vigna radiata (L.) Wilcz., (syn. V. aureus, Phaseolus aureus), English mung bean, green gram, golden gram, chop suey bean, moong.
Vigna radiata is thought to have originated in the India-Burma region of Southeast Asia, from where it was introduced to many other regions of the world. The wild mung bean, Vigna vexillata, is a climbing plant that grows wild in the foothills of the Himalayas and northern India, but is sometimes cultivated. However, wild forms of V. radiata have never been found, although wild progenitor species have been identified in India, which is a major production area.
Annual semi-erect plants are 0.5 to 1 m tall, with numerous branches covered with short brownish hairs and three-leafed leaves resembling those of the pea. Short- and long-day varieties are grown. The self-fertile flowers produce pods 5-10 cm long and 0.5 cm thick which mature about 20 days after flowering. The pods usually contain 10 or more small elongated or round seeds in a dark olive green or yellow color; some plants produce brown or black seeds.
Seeds are usually sown in a scattered manner, but in row planting, the usual distance between rows is 5 to 10 cm, and the distance between rows is 70-90 cm. Row planting is often used because it facilitates tillage for weed control, which broadcast planting does not. Annual production is estimated at 2.5 to 3 million tons from about 5 million hectares; this is about 5% of all legumes produced. The main production area extends from South Asia to Southeast Asia.
Mungbean is a very important crop in India, where the green immature pods are used as vegetables, although their main use is as a legume for making dal, a porridge-like dish. Varieties yielding yellow seeds (golden gram) are mostly used for this purpose. One reason for the popularity of mash is that it causes less flatulence.
Other countries, especially China, grow varieties with green seeds (green gram) to produce seeds that are used after germination. The seeds are soaked, germinated, and left to grow in the dark for several days, after which they are harvested for use. One gram of seed yields 6-8 grams of fresh sprouts. Etiolated hypocotyls, young cotyledon leaves and young root radicles are eaten boiled or uncooked with other vegetable dishes. Sprouts are a good source of vitamin C. The carbohydrate content of the dried seeds is 55% to 60% and the protein content is about 23%. The tuberous roots of mungbean are of some interest because of their protein content of almost 15%.
Bambara groundnut (Vigna subterranea)
Bambara groundnut, Vigna subterranea (L.) Verdn. (syn. Voandzeia subterranea), bambara groundnut.
Vigna subterranea is a native species of west-central Africa, and most of the cultivated bambara groundnut is produced in the arid regions of tropical western Africa. Semi-ripe seeds are used for fresh vegetables. The mature seeds are used as a legume crop, mainly for making porridges and similar dishes. Dried seeds are very hard and require a long cooking time to become tasty. The trypsin inhibitor is also inactivated during cooking.
Branched, relatively short, side-growing plants produce adventitious roots in the internodes of the stems as they spread over the ground. The root is well developed and forms many lateral roots. Because of the distance between the internodes, the plant varies in height from bushy to spreading; bushy species usually mature earlier. The leaves are pinnately trifoliate, on upright, grooved petioles. Plants are annuals with an indeterminate flowering period; some varieties require a short day to bloom.
Bambara groundnut is prized for its drought tolerance and ability to work in poor soils, which provides some yield. Well-drained, slightly acidic (pH 5.0-6.5) and loose soil is preferred, especially to facilitate pod penetration and development in the soil. High fertility should be avoided because it enhances foliage growth to the detriment of pod development.
Plantings are established using seeds, usually sown to a depth of about 5 cm. Seed viability is relatively low, and germination is slow and often poor because of the hard seed coat. Crops are grown in mixed crops about as often as in pure stands. Plant densities in pure stands range from 6 to 12 plants/m2. A higher density is used if there is sufficient moisture. A uniform moisture level of about 900 mm is optimal.
Favorable growing temperatures range from 20°C to 28°C, and a minimum of 3-4 months is required for a mature crop, with late varieties requiring 5-7 months. Plants are intolerant of frost, but tolerate high temperatures.
Flowering begins 40-50 days after sprouting and continues uninterrupted. The pale yellow flowers are self-pollinated. After pollination, the flower stalks elongate and grow to the soil surface or slightly below it. The nearly round pods are 2-3 cm in diameter and usually resemble peanuts (groundnuts) in their underground development. The pods usually contain one smooth, nearly round seed; the color of the seed depends on the variety. The seeds mature as early as 50 days after fertilization, but some late varieties require more than 100 days. Mature seeds are 8 to 10 mm in diameter and weigh 0.5 to 0.7 g. per seed.
Plants are harvested by digging out and removing the pods. Harvesting the pods separated from the soil is often required to obtain a full crop. Bush varieties, with their concentrated production, are easier to harvest than sprawling varieties. Seed removal from the pods is difficult, but is usually done by hand. Yields of over 3500 kg/ha have been obtained. In the rainfed, arid regions of Africa, yields average about 750 kg/ha. Global annual production is about 330,000 tons, most of which is produced in West Africa.
Rice bean (Vigna umbellata)
Rice bean, Vigna umbellata (Thumb.) Ohwi & Ohashi (syn. Phaseolus calcaratus), English red bean, rice bean.
The origin of the rice bean is unknown, although wild forms are found over a wide geographic area from the foothills of the Himalayas to mid-China and as far south as Malaysia. The plants are tolerant of high temperatures and fairly drought tolerant. They are short-day annuals with semi-erect or climbing growth, with stems reaching 1 to 3 m in length. Yellow self-fertile flowers produce long (6-12 cm) and thin (0.5 cm) pods containing 6-12 small oblong seeds.
Immature pods and young leaves are eaten as vegetables. Dried beans are often cooked with rice or as an alternative to rice dishes, hence the common name. Dried seeds contain about 55-60% carbohydrates and 21% protein and store well. Plants are often chosen to grow in rotation with rice crops, either for use as vegetables or sometimes as a green fertilizer.
Cowpea (Vigna unguiculata)
Several cultural groups are distinguished:
- common cowpea, Vigna unguiculata L. Walp. cultural group unguiculata, English common cowpea, other names blackeye pea, southern pea, crowder pea, frijole, coupe, lubia, niebe, kaffir bean;
- cowpea catjang, Vigna unguiculata L. Walp. cultural group cylindrica, English catjang cowpea, other names: Bombay cowpea, Jerusalem pea, marble pea;
- cowpea longiflorum, Vigna unguiculata (L.) Walp. cultural group sesquipedalis, yardlong bean, other names: snake bean, asparagus bean, sitao, bodi bean.
Common cowpea, katjang, and long cowpea are collectively considered one species, and these three cultural groups of V. unguiculata can easily interbreed. The term “cultural groups” is more appropriate than subspecies for these pea species because there are few genetic differences. Cowpea is an important vegetable and is also widely known as a major legume crop. The domestication of the common cowpea most likely occurred in the tropical West African savannah, but the variety of wild relatives of the pea is found in southeastern Africa. Common cowpea is widely cultivated in Africa, while its relatives katjang and long-fruited cowpea are not, but are well represented in India and Southeast Asia, respectively. Long-fruited cowpea is widely cultivated in China.
These cultivated groups of V. unguiculata have been cultivated for centuries. The edible tender shoots, leaves, immature pods, fresh herbs and dried seeds are edible products of each. Their combined annual production from more than 5 million hectares contributes significantly to meeting the dietary protein needs of millions of people. The value of this crop is particularly evident in the tropical and subtropical regions of Africa, where the common cowpea is the second most important legume crop; it is also very important in Brazil.
The different species of cowpea have some common features. They are annual plants that develop strong roots with numerous lateral outgrowths. Optimal growth occurs at a temperature of 27-30°C during the day and 17-22°C at night. Cowpea tolerates heat and dry conditions better than common field or lima beans, but it is very sensitive to air and soil temperatures below 20°C. The preferred soil texture is loamy sandy loam. Plants are sensitive to waterlogging.
Cultivated varieties of common cowpea vary widely from growth-prone indeterminant short-day to upright determinant and day-neutral plants. Flowers are usually self-pollinated and vary in color from yellowish-white to purple. Plants produce many finger-shaped pods that are pendant. The pods reach 10-30 cm in length and contain seeds, usually with a dark outline or eye around the tubercle, so some varieties are often called black bean or pea. Other basic types are called “purple hull” and “cream” because of the color of the pods of the former and the color of the seeds of the latter. The “crowder” type usually refers to peas whose pods are overflowing with seeds. There are many varieties within each type, but only some of them produce edible fresh pods. Early-ripening varieties produce immature pods in as little as 40 days, and fresh mature seeds in 60 days. In some situations, common peas are grown in mixed crops rather than pure. If crops are not scattered, plant spacing is usually 5-10 cm in a row and 70-90 cm between rows.
Fresh immature seeds and pods are eaten cooked; in the United States fresh or dried seeds are processed by canning and freezing. The carbohydrate and protein content of dried cowpea seeds is over 50% and 20%, respectively. The tender shoots and leaves are consumed as food. Varieties that tolerate frequent pruning of shoots and removal of leaves are grown for consumption. Some varieties are used in this way with relatively little loss in yield of fresh pods and seeds.
Long-fruited cowpea is the most vegetable-like of all pea varieties. The stems of trailed or climbing plants reach several meters in length. During growth, the stems are maintained on a trellis to prevent the pods from coming into contact with the ground and to ensure direct pod development. Plants are easily stressed by a lack of moisture, but tolerate rain and high humidity better than other pea species.
Flowers begin to appear as early as 4-6 weeks after sprouting, and edible pods are formed about 2 weeks after oviposition. However, harvesting most often begins about 70 days after planting and can last for 25-30 days. The pods are 30-80 cm long and sometimes longer. The slender, hanging pods are used as string beans. The short postharvest life of long-fruited cowpea pods is due to heavy respiration and wilting. Although low-temperature storage extends the shelf life of harvested pods, long-fruited cowpeas are sensitive to cold and become damaged even after a few days at temperatures below 10°C.
The pods look kind of bloated, and as the seeds mature, they become shrunken. Fresh mature seeds, although less preferable than those of the common pea, are also eaten as string beans. The mature seeds, which are rarely eaten, are kidney-shaped, vary in length from 6 to 12 mm, and are usually reddish brown or black. Long-fruited cowpea pods are a popular vegetable in Southeast Asia, China, the Philippines and the Caribbean. Edible pod production in China is over 250,000 ha; yields range from 4 to 10 t/ha. In Indonesia, young leaves and shoots are eaten as herbs. The bush variety (bush sitao) was bred by crossing long-fruited and common cowpea. Unlike the long-fruited cowpea, this plant produces shorter, edible pods and does not need a trellis. Its popularity is highest in the Philippines and is likely to spread throughout Southeast Asia. In the U.S., bush varieties produce 25-28 t/ha of edible pods.
Cowpea katjang is semi-erect; the pods grow vertically, are 7-12 cm long, and produce many small seeds that are used as vegetables when immature. This crop is popular in India for use as a legume crop. The plant is also used as animal feed.
Background of current types
There are a significant number of similarities in the genetic, physiological, and adaptive characteristics of legume food crop species, allowing them to be considered together as well as genus by genus. The most significant historical work on peas (Pisum sativum) was done by Mendel (1866). Although his work was overlooked by most applied botanists until it was rediscovered around the same time by Correns (1900), de Vries and Cermak in Germany, and William Bateson in Cambridge (Bateson, 1901; Druery and Bateson, 1901), it remains fundamental to the genetic understanding of all plant and animal species studied. Peas are largely self-pollinated and therefore inbreeding species, as are common beans Phaseolus vulgaris (but not Phaseolus multifl orus syn. P. coccineus). Wild landraces (now considered as locally adapted ecotypes) of such largely inbreeding species are mixtures of mostly homozygous plants and heterozygotes from crosses that occurred naturally as a result of insect pollination, facilitated by the shape of the flowers and the presence of nectar. Beans were studied by W.L. Johannsen in Denmark, who found different effects on genotypes when exposed to environmental factors, i.e. phenotype (Pierson, 2012). This work is also related to trait expression in barley and provides information related to inbreeders, where populations based on “pure lines” are required by seed growers and traders needing stable varieties for marketing. Vicia faba, however, is largely outbreeding, with individual flowers on any plant easily pollinated by pollen from other flowers on the same or other plants in the population. In outbreeders, self-pollination may be forced, but the plants produced from seed are often weaker or different from typical plants of the parent population. Line selection in these species does not produce satisfactory new varieties, but “inbreeding depression” is common, while forms of “mass selection” allow useful named populations to be obtained, grown, and sold. However, significant improvement can be achieved with a strategy of “synthetic” variety breeding, in which a variety is created by crossing in all combinations of a number of inbred lines that combine well with each other. After synthesis, the synthetic variety is maintained by open pollination in isolation. This strategy has been applied in several bean-producing countries.
The second group of important similarities concerns diseases of these three crop species and the breeding strategies involved in their treatment and control. These diseases can result from soil-borne infections, spore dispersal, bacteria spread to surrounding plants by rain or spray, or fungal or bacterial seed-borne pathogens. As a result, selection for disease resistance has become an important part of the overall plant breeding effort. Finding, documenting, and sometimes effectively using sources of disease resistance has played a significant role in major germplasm collections over the past 70 years, but it began with two areas: the Vavilov Institute collections for the former Soviet Union and the US Plant Introduction Service collections, cataloged by plant introduction number (PI). There is also curation of these collections, such as Pisum at the John Innes Institute in Norwich, UK, and especially the work at Cambridge University with the PI set sub-collection used in Uganda as part of the Aid initiative (Leakey, 1970).
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