A legume () is a

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

in the family Fabaceae (or Leguminosae), or the

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animal ...

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used ...

and

silage Silage () is a type of fodder made from green foliage crops which have been preserved by fermentation to the point of acidification. It can be fed to cattle, sheep and other such ruminants (cud-chewing animals). The fermentation and storage ...

, and as soil-enhancing green manure. Well-known legumes include beans,

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu a ...

s, chickpeas,

peanut The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics, important to both small and ...

lentil The lentil (''Lens culinaris'' or ''Lens esculenta'') is an edible legume. It is an annual plant known for its lens-shaped seeds. It is about tall, and the seeds grow in pods, usually with two seeds in each. As a food crop, the largest pro ...

s, lupins,

mesquite Mesquite is a common name for several plants in the genus '' Prosopis'', which contains over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under gr ...

, carob,

tamarind Tamarind (''Tamarindus indica'') is a leguminous tree bearing edible fruit that is probably indigenous to tropical Africa. The genus ''Tamarindus'' is monotypic, meaning that it contains only this species. It belongs to the family Fabaceae ...

, alfalfa, and

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

. Legumes produce a botanically unique type of fruit – a simple dry fruit that develops from a simple

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils' ...

and usually dehisces (opens along a seam) on two sides. Legumes are notable in that most of them have symbiotic nitrogen-fixing

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

in structures called root nodules. For that reason, they play a key role in crop rotation.

Terminology

The term ''pulse'', as used by the United Nations'

Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

(FAO), is reserved for legume crops harvested solely for the dry seed. This excludes green beans and green peas, which are considered

vegetable Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the flowers, fruits, stems, ...

crops. Also excluded are seeds that are mainly grown for oil extraction (

oilseed Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...

s like

s and

s), and seeds which are used exclusively for sowing

(

s, alfalfa). However, in common usage, these distinctions are not always clearly made, and many of the varieties used for dried pulses are also used for green vegetables, with their beans in pods while young. Some Fabaceae, such as Scotch broom and other

Genisteae Genisteae is a tribe of trees, shrubs and herbaceous plants in the subfamily Faboideae of the family Fabaceae. It includes a number of well-known plants including broom, lupine (lupin), gorse and laburnum. The tribe's greatest diversity is in ...

, are leguminous but are usually not called legumes by farmers, who tend to restrict that term to food crops.

History

Neanderthal Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. While the ...

s used pulses when cooking meals 70,000 years ago. Archaeologists have discovered traces of pulse production around

Ravi River The Ravi River () is a transboundary river crossing northwestern India and eastern Pakistan. It is one of five rivers associated with the Punjab region. Under the Indus Waters Treaty of 1960, the waters of the Ravi and two other rivers were ...

(

Punjab Punjab (; Punjabi: پنجاب ; ਪੰਜਾਬ ; ; also romanised as ''Panjāb'' or ''Panj-Āb'') is a geopolitical, cultural, and historical region in South Asia, specifically in the northern part of the Indian subcontinent, comprising a ...

), the seat of the

Indus Valley civilisation The Indus Valley Civilisation (IVC), also known as the Indus Civilisation was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form 2600 BCE to 1900& ...

, dating to c. 3300 BCE. Meanwhile, evidence of lentil cultivation has also been found in Egyptian pyramids and

cuneiform Cuneiform is a logo-syllabic script that was used to write several languages of the Ancient Middle East. The script was in active use from the early Bronze Age until the beginning of the Common Era. It is named for the characteristic wedge-sh ...

recipes. Dry pea seeds have been discovered in a Swiss village that are believed to date back to the Stone Age. Archaeological evidence suggests that these peas must have been grown in the eastern Mediterranean and

Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...

n regions at least 5,000 years ago and in Britain as early as the 11th century. The soybean was first domesticated around 5,000 years ago in China from a descendant of the wild vine ''Glycine soja.'' In the United States, the domesticated soybean was introduced in 1770 by

Benjamin Franklin Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading inte ...

after he sent seeds to Philadelphia from France.

Henry Ford Henry Ford (July 30, 1863 – April 7, 1947) was an American industrialist, business magnate, founder of the Ford Motor Company, and chief developer of the assembly line technique of mass production. By creating the first automobile that ...

, a vegetarian, was the first person to use soybeans for large-scale industrial purposes. Concentrating on his company, from 1932 to 1933 he invested over 1 million dollars in research on soybeans. Prior to

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, 40% of cooking oil was imported into the US. When the war came, supply routes were disrupted, which encouraged the soybean culture in the US. Due to the years of research done by

, the domestic soybean oil industry was born. Between 1970 and 1976, soybean production increased approximately 30%. Oil yield from bulk soybeans averages about 18%. Its modern-day usage ranges from margarine, salad oils, shortening and the previously mentioned cooking oil.

Uses

Farmed legumes can belong to many agricultural classes, including

, grain, blooms, pharmaceutical/industrial, fallow/green manure, and timber species. Most commercially farmed species fill two or more roles simultaneously, depending upon their degree of maturity when harvested.

Human consumption

Grain legumes are cultivated for their seeds, which are used for human and animal consumption or for the production of oils for industrial uses. Grain legumes include beans,

s, lupins, peas, and

s. Legumes are used as a key ingredient in vegan meat and dairy substitutes. They are growing in use as a plant-based protein source in the world marketplace. Products containing legumes grew by 39% in Europe between 2013 and 2017.

Nutritional value

Legumes are a significant source of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

, dietary fiber,

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

s and

dietary minerals In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, ...

; for example, a 100 gram serving of cooked chickpeas contains 18 percent of the

Daily Value The Reference Daily Intake (RDI) used in nutrition labeling on food and dietary supplement products in the U.S. and Canada is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of healthy ...

(DV) for protein, 30 percent DV for dietary fiber, 43 percent DV for

folate Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing an ...

and 52 percent DV for

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

. Legumes are also an excellent source of

resistant starch Resistant starch (RS) is starch, including its degradation products, that escapes from digestion in the small intestine of healthy individuals. Resistant starch occurs naturally in foods, but it can also be added as part of dried raw foods, or use ...

which is broken down by

in the

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before bein ...

to produce

short-chain fatty acid Short-chain fatty acids (SCFAs) are fatty acids with fewer than six carbon atoms. Derived from intestinal microbial fermentation of indigestible foods, SCFAs are the main energy source of colonocytes, making them crucial to gastrointestinal healt ...

s (such as butyrate) used by intestinal cells for

food energy Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohy ...

Forage

Forage legumes are of two broad types. Some, like alfalfa,

, vetch (''

Vicia ''Vicia'' is a genus of over 240 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other ...

''), stylo (''

Stylosanthes ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. The ...

''), or ''

Arachis ''Arachis'' is a genus of about 70 species of annual and perennial flowering plants in the family (Fabaceae), native to South America, and was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. At least one ...

'', are sown in

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or sw ...

and grazed by livestock. Other forage legumes such as '' Leucaena'' or ''

Albizia ''Albizia'' is a genus of more than 160 species of mostly fast-growing subtropical and tropical trees and shrubs in the subfamily Mimosoideae of the family Fabaceae. The genus is pantropical, occurring in Asia, Africa, Madagascar, America and A ...

'' are woody shrub or tree species that are either broken down by livestock or regularly cut by humans to provide livestock feed. Legume-based feeds improve animal performance compared to a diet of perennial grasses. Factors to which this is attributed are larger consumption, faster digestion and higher feed conversion rate. The type of crop(s) grown or animal rearing will be dependent on the farming system, either vegetables,

tubers Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing s ...

, grains, cattle etc. In cattle rearing, legume trees such as '' Gliricidia sepium'' can be planted along edges of field to provide shade for cattle, the leaves and bark are often eaten by cattle. Green manure can also be grown between periods when crops of economic importance are harvested prior to the next crops to be planted.

Other uses

Legume species grown for their flowers include lupins, which are farmed commercially for their blooms as well as being popular in gardens worldwide. Industrially farmed legumes include ''

Indigofera ''Indigofera'' is a large genus of over 750 species of flowering plants belonging to the pea family Fabaceae. They are widely distributed throughout the tropical and subtropical regions of the world. Description Species of ''Indigofera'' are mos ...

'' and '' Acacia'' species, which are cultivated for dye and natural gum production, respectively.

Fallow Fallow is a farming technique in which arable land is left without sowing for one or more vegetative cycles. The goal of fallowing is to allow the land to recover and store organic matter while retaining moisture and disrupting pest life cycl ...

or green manure legume species are cultivated to be tilled back into the soil in order to exploit the high levels of captured atmospheric nitrogen found in the roots of most legumes. Numerous legumes farmed for this purpose include '' Leucaena'', '' Cyamopsis'', and '' Sesbania'' species. Various legume species are farmed for timber production worldwide, including numerous '' Acacia'' species and '' Castanospermum australe''. Some legume trees, like the

honey locust The honey locust (''Gleditsia triacanthos''), also known as the thorny locust or thorny honeylocust, is a deciduous tree in the family Fabaceae, native to central North America where it is mostly found in the moist soil of river valleys. Hon ...

(''

Gleditsia ''Gleditsia'' (honey locust) is a genus of trees in the family Fabaceae, subfamily Caesalpinioideae, native to North America and Asia. The Latin name commemorates Johann Gottlieb Gleditsch, director of the Berlin Botanical Garden, who died in 1 ...

'') can be used in agroforestry. Others, including the

black locust ''Robinia pseudoacacia'', commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belonging to the tribe Robinieae of the legume family Fabaceae. It is endemic to a few small areas of the United States ...

(''

Robinia pseudoacacia ''Robinia pseudoacacia'', commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belonging to the tribe Robinieae of the legume family Fabaceae. It is endemic to a few small areas of the United States, ...

''), Kentucky coffeetree (''

Gymnocladus dioicus The Kentucky coffeetree (''Gymnocladus dioicus''), also known as American coffee berry, Kentucky mahogany, nicker tree, and stump tree, is a tree in the subfamily Caesalpinioideae of the legume family Fabaceae, native to the Midwest, Upper South, ...

''), ''

Laburnum ''Laburnum'', sometimes called golden chain or golden rain, is a genus of two species of small trees in the subfamily Faboideae of the pea family Fabaceae. The species are '' Laburnum anagyroides''—common laburnum and '' Laburnum alpinum''� ...

,'' and the woody climbing vine ''

Wisteria ''Wisteria'' is a genus of flowering plants in the legume family, Fabaceae (Leguminosae), that includes ten species of woody twining vines that are native to China, Japan, Korea, Vietnam, Southern Canada, the Eastern United States, and north ...

'', have poisonous elements.

Classification

FAO The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

recognizes 11 primary pulses. The FAO notes that the term "pulses" is limited to legumes harvested solely for dry grain, thereby excluding legumes that are harvested green for food (green peas, green beans, etc.) which are classified as vegetable crops. Also excluded are those legumes used mainly for oil extraction (e.g., soybeans and groundnuts) or used exclusively for sowing purposes (e.g., seeds of clover and alfalfa). # Dry beans (FAOSTAT code 0176, '' Phaseolus'' spp. including several species now in ''

Vigna ''Vigna'' is a genus of plants in the legume family, Fabaceae, with a pantropical distribution.Aitawade, M. M., et al. (2012)Section ''Ceratotropis'' of subgenus ''Ceratotropis'' of ''Vigna'' (Leguminosae–Papilionoideae) in India with a new ...

'') #* Kidney bean, navy bean,

pinto bean The pinto bean () is a variety of common bean (''Phaseolus vulgaris''). In Spanish they are called , literally "painted bean" (compare pinto horse). It is the most popular bean by crop production in Northern Mexico and the Southwestern United Sta ...

, black turtle bean, haricot bean ('' Phaseolus vulgaris'') #*

Lima bean A lima bean (''Phaseolus lunatus''), also commonly known as the butter bean, sieva bean, double bean, Madagascar bean, or wax bean is a legume grown for its edible seeds or beans. Origin and uses ''Phaseolus lunatus'' is found in Meso- and Sou ...

, butter bean (''

Phaseolus lunatus A lima bean (''Phaseolus lunatus''), also commonly known as the butter bean, sieva bean, double bean, Madagascar bean, or wax bean is a legume grown for its edible seeds or beans. Origin and uses ''Phaseolus lunatus'' is found in Meso- and Sou ...

'') #* Adzuki bean, azuki bean ('' Vigna angularis'') #* Mung bean, golden gram, green gram ('' Vigna radiata'') #*

Black gram ''Vigna mungo'', also known as black gram, urad bean, urid bean, mash kalai, uzhunnu parippu, ulundu paruppu, minapa pappu, uddu, or black matpe, is a bean grown in South Asia. Like its relative, the mung bean, it has been reclassified from the ...

, urad (''

Vigna mungo ''Vigna mungo'', also known as black gram, urad bean, urid bean, mash kalai, uzhunnu parippu, ulundu paruppu, minapa pappu, uddu, or black matpe, is a bean grown in South Asia. Like its relative, the mung bean, it has been reclassified from the ...

'') #* Scarlet runner bean (''Phaseolus coccineus'') #* Ricebean (''Vigna umbellata'') #*

Moth bean ''Vigna aconitifolia'' is a drought-resistant legume, commonly grown in arid and semi-arid regions of India. It is commonly called mat bean, moth bean, matki or dew bean. The pods, sprouts and protein-rich seeds of this crop are commonly consu ...

(''Vigna aconitifolia'') #*

Tepary bean ''Phaseolus acutifolius'', also known as the tepary bean, is a legume native to the southwestern United States and Mexico and has been grown there by the native peoples since pre-Columbian times. It is more drought-resistant than the common bean ...

(''Phaseolus acutifolius'') # Dry

broad beans ''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Var ...

(code 0181, ''Vicia faba'') #* Horse bean (''Vicia faba equina'') #* Broad bean (''Vicia faba'') #* Field bean (''Vicia faba'') # Dry peas (code 0187, ''Pisum'' spp.) #* Garden pea (''Pisum sativum'' var. ''sativum'') #* Protein pea (''Pisum sativum'' var. ''arvense'') # Chickpea, garbanzo, Bengal gram (code 0191, ''Cicer arietinum'') # Dry

cowpea The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus ''Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few inputs, ...

black-eyed pea The black-eyed pea or black-eyed bean is a legume grown around the world for its medium-sized, edible bean. It is a subspecies of the cowpea, an Old World plant domesticated in Africa, and is sometimes simply called a cowpea. The common commer ...

, blackeye bean (code 0195, ''Vigna unguiculata'') #

Pigeon pea The pigeon pea (''Cajanus cajan'') is a perennial legume from the family Fabaceae native to the Old World. The pigeon pea is widely cultivated in tropical and semitropical regions around the world, being commonly consumed in South Asia, South ...

, Arhar/Toor, cajan pea, Congo bean, gandules (code 0197, ''Cajanus cajan'') #

Lentil The lentil (''Lens culinaris'' or ''Lens esculenta'') is an edible legume. It is an annual plant known for its lens-shaped seeds. It is about tall, and the seeds grow in pods, usually with two seeds in each. As a food crop, the largest pro ...

(code 0201, ''Lens culinaris'') #

Bambara groundnut ''Vigna subterranea'' (common names: Bambara groundnut, Bambara nut, Bambara bean, Congo goober, earth pea, ground-bean, or hog-peanut) is a member of the family Fabaceae. Its name is derived from the Bambara tribe, who currently lives in Mali. T ...

, earth pea (code 0203, ''Vigna subterranea'') #

Vetch ''Vicia'' is a genus of over 240 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other ...

, common vetch (code 0205, ''Vicia sativa'') # Lupins (code 0210, ''Lupinus'' spp.) # Pulses NES (code 0211), Minor pulses, including: #* Lablab, hyacinth bean ('' Lablab purpureus'') #* Jack bean ('' Canavalia ensiformis''), sword bean ('' Canavalia gladiata'') #* Winged bean ('' Psophocarpus tetragonolobus'') #* Velvet bean, cowitch ('' Mucuna pruriens var. utilis'') #* Yam bean (''

Pachyrhizus erosus ''Pachyrhizus erosus'', commonly known as jícama ( or ; Spanish ''jícama'' ; from Nahuatl ''xīcamatl'', ) Mexican turnip, is the name of a native Mexican vine, although the name most commonly refers to the plant's edible tuberous root. Jíca ...

'')

Pollination

Legumes can either be self-pollinated or

cross-pollinated Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

. Some tropical legumes that are closely self-pollinated are: '' Macroptilium atropurpureum'' 'Siratro', '' Macroptilium lathyroides'', '' Centrosema pubescens'', '' Neonotonia wightii'', and '' Lotononis bainesii''. However, the

autogamous Autogamy, or self-fertilization, refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of ...

annual ''

Stylosanthes humilis ''Stylosanthes humilis'', the Townsville stylo, is a species of flowering plant in the family Fabaceae, native to the New World Tropics, and widely introduced as a forage Forage is a plant material (mainly plant leaves and stems) eaten by graz ...

'' proved otherwise by adapting in response to changing conditions during an experiment, and was found to be composed of several genotypes showing heterogeneity. Two legumes used for pasture with

cross-pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, bird ...

are '' Desmodium intortum'' and '' Desmodium uncinatum''. When the flower is opened, this is the only time fertilization will take place. These two species' characteristics vary in

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

and ruggedness.

Nitrogen fixation

Many legumes contain symbiotic bacteria called '' Rhizobia'' within root nodules of their

root systems In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often b ...

(plants belonging to the genus ''

Styphnolobium ''Styphnolobium'' is a small genus of three or four species of small trees and shrubs in the subfamily Faboideae of the pea family Fabaceae, formerly included within a broader interpretation of the genus '' Sophora''. It was recently assigned to ...

'' are one exception to this rule). These bacteria have the special ability of fixing nitrogen from atmospheric, molecular nitrogen (N₂) into

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

(NH₃). The chemical reaction is: :N₂ + 8H⁺ + 8e⁻ → 2NH₃ + H₂ Ammonia is then converted to another form, ammonium (NH), usable by (some) plants by the following reaction: :NH₃ + H⁺ → NH This arrangement means that the root nodules are sources of nitrogen for legumes, making them relatively rich in

plant proteins Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude ...

. All proteins contain nitrogenous

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s. Nitrogen is therefore a necessary ingredient in the production of proteins. Hence, legumes are among the best sources of plant protein. When a legume plant dies in the field, for example following the harvest, all of its remaining nitrogen, incorporated into

s inside the remaining plant parts, is released back into the soil. In the soil, the amino acids are converted to nitrate (NO), making the nitrogen available to other plants, thereby serving as fertilizer for future crops. Nitrogen Cycle

In many traditional and organic farming practices, crop rotation involving legumes is common. By alternating between legumes and non-legumes, sometimes planting non-legumes two times in a row and then a legume, the field usually receives a sufficient amount of nitrogenous compounds to produce a good result, even when the crop is non-leguminous. Legumes are sometimes referred to as " green manure". Sri Lanka developed the farming practice known as coconut-soybean intercropping. Grain legumes are grown in coconut (''Cocos nuficera'') groves in two ways: intercropping or as a cash crop. These are grown mainly for their protein, vegetable oil and ability to uphold soil fertility. However, continuous cropping after 3–4 years decrease grain yields significantly.

Distribution and production

Legumes are widely distributed as the third-largest

land plant The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sist ...

family in terms of number of species, behind only the

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

and

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

, with about 751 genera and some 19,000 known species, constituting about seven percent of flowering plant species.

Storage

Seed viability decreases with longer storage time. Studies done on

vetch ''Vicia'' is a genus of over 240 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other ...

broad bean ''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Varieti ...

s, and peas show that they last about 5 years in storage. Environmental factors that are important in influencing germination are relative humidity and temperature. Two rules apply to moisture content between 5 and 14 percent: the life of the seed will last longer if the storage temperature is reduced by 5 degree Celsius. Secondly, the storage moisture content will decrease if temperature is reduced by 1 degree Celsius.

Pests and diseases

A common pest of grain legumes that is noticed in the tropical and subtropical Asia, Africa, Australia and Oceania are minuscule flies that belong to the family ''

Agromyzidae The Agromyzidae are a family commonly referred to as the leaf-miner flies, for the feeding habits of their larvae, most of which are leaf miners on various plants. A worldwide family of roughly 2,500 species, they are small, some with wing l ...

'', dubbed "bean flies". They are considered to be the most destructive. The host range of these flies is very wide amongst cultivated legumes. Infestation of plants starts from germination through to harvest, and they can destroy an entire crop in early stage.

Black bean aphid The black bean aphid (''Aphis fabae'') is a small black insect in the genus ''Aphis'', with a broad, soft body, a member of the order Hemiptera. Other common names include blackfly, bean aphid, and beet leaf aphid. In the warmer months of the yea ...

s are a serious pest to broad beans and other beans. Common hosts for this pest are fathen, thistle and dock. Pea weevil and

bean weevil The bean weevils or seed beetles are a subfamily (Bruchinae) of beetles, now placed in the family Chrysomelidae, though they have historically been treated as a separate family. They are granivores, and typically infest various kinds of seeds or ...

damage leaf margins leaving characteristics semi-circular notches. Stem nematodes are very widespread but will be found more frequently in areas where host plants are grown. Common legume diseases include anthracnose, caused by '' Colletotrichum trifolii''; common leaf spot caused by ''

Pseudomonas syringae ''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from intern ...

pv. syringae''; crown wart caused by '' Physoderma alfalfae'';

downy mildew Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of cruc ...

caused by '' Peronospora trifoliorum''; fusarium root rot caused by ''

Fusarium ''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...

'' spp.; rust caused by '' Uromyces striatus''; sclerotina crown and stem rot caused by ''

Sclerotinia trifoliorum ''Sclerotinia trifoliorum'' is a plant pathogen infecting alfalfa, red clover ''Trifolium pratense'', the red clover, is a herbaceous species of flowering plant in the bean family Fabaceae, native to Europe, Western Asia, and northwest Af ...

''; Southern blight caused by '' Sclerotium rolfsii''; pythium (browning) root rot caused by ''

Pythium ''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but ''Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequen ...

'' spp.; fusarium wilt caused by ''

Fusarium oxysporum ''Fusarium oxysporum'' (Schlecht as emended by Snyder and Hansen), an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. It is part of ...

'';

root knot In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

caused by '' Meloidogyne hapla''. These are all classified as biotic problems. Abiotic problems include nutrient deficiencies, (nitrogen, phosphorus, potassium, copper, magnesium, manganese, boron, zinc), pollutants (air, water, soil, pesticide injury, fertilizer burn), toxic concentration of minerals, and unfavorable growth conditions.

International Year of Pulses

The International Year of Pulses 2016 (IYP 2016) was declared by the Sixty-eighth session of the United Nations General Assembly. The

Food and Agriculture Organization of the United Nations The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

was nominated to facilitate the implementation of IYP 2016 in collaboration with governments, relevant organizations, non-governmental organizations and other relevant stakeholders. Its aim was to heighten public awareness of the nutritional benefits of pulses as part of sustainable food production aimed towards

food security Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World ...

and

nutrition Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient ...

. IYP 2016 created an opportunity to encourage connections throughout the food chain that would better use pulse-based proteins, further global production of pulses, better use crop rotations and address challenges in the global trade of pulses.

References

External links

* * {{Authority control Fruit morphology Staple foods Vegetables Vegetarian cuisine