General descriptions of Legumes Plants With Examples, Importance

What are Legumes?

• Legumes, a significant category within the plant kingdom, are second only to cereals in their role as sources of human nutrition. These plants are notable for their high protein content, which surpasses that of other vegetable products, making them nearly equivalent to animal flesh in terms of dietary value. In addition to proteins, legumes contain carbohydrates and fats, providing a balanced nutrient profile.
• Proteins in legumes are stored as granules within cells that also contain starch grains. This high protein concentration is associated with the presence of tubercles on the roots of many legumes, which house nitrogen-fixing bacteria. These bacteria are crucial because they convert atmospheric nitrogen into nitrates, enhancing the availability of nitrogenous compounds for the plants.
• Legumes are members of the family Leguminosae, characterized by their unique fruit type, known as a legume. This fruit is a pod that splits open along two seams when ripe. There are approximately 11,000 known species within this family, many of which are crucial for industrial, medicinal, and dietary purposes. Legumes have been cultivated globally for centuries, with their seeds being particularly valued due to their low water content and protective seed coats, which enhance their storage capability and longevity.
• Furthermore, legumes are easy to cultivate, grow quickly, and are highly nutritious. They are especially important in regions where meat consumption is limited, having historically formed a substantial part of the diet for poorer populations in Europe before the widespread adoption of the potato. Their high energy content makes them well-suited for cold climates and physically demanding activities.
• In addition to their edible seeds, all parts of the legume plant are rich in protein, which makes them valuable as field and forage crops. When legumes are plowed under, they act as an excellent fertilizer, significantly improving the nitrogen content of the soil. This dual function of providing nutrition and enhancing soil fertility underscores their importance in agricultural systems.

Examples of Legumes

Legumes encompass a wide range of plants, each with distinct characteristics and uses. The following are notable examples, categorized by their types and key attributes:

1. Peas (Pisum sativum)
   • Origin and Distribution: Native to Southern Europe, the common pea has been cultivated since ancient times. Although known to the Greeks and Romans, its widespread cultivation in Europe began in the mid-seventeenth century. Peas are well-suited to cooler climates with ample moisture, thriving particularly in Canada and the northern United States.
   • Characteristics: Peas are annual, tendril-bearing plants with climbing or trailing habits. They feature white or colored flowers and pendulous pods. There are two primary types: field peas and garden peas.
     • Field Peas: Originating possibly from the gray pea of Greece, these are hardy, with angular seeds and colored flowers. They withstand frost and high altitudes, and are used for human consumption in the form of pea meal or split peas, and as livestock feed.
     • Garden Peas: These have white flowers and smooth or wrinkled seeds. They contain more sugar than field peas and are consumed fresh, canned, or used for processing into various products. Garden peas are notable for their role in Gregor Mendel’s genetic experiments.
   • Uses: Both types are consumed directly or processed. Field peas are also used in animal feed, while garden peas are important in the canning industry.
2. Chickpeas (Cicer arietinum)
   • Origin and Distribution: Native to Southern Europe, chickpeas are extensively cultivated in Asia, Africa, and Central America. India, in particular, grows a substantial amount of chickpeas.
   • Characteristics: Chickpeas are bushy annual plants that mature in about 90 days. They are well-adapted to arid and semiarid regions and are highly nutritious.
   • Uses: Chickpeas are used in various culinary applications, including as a coffee substitute. The seeds are rich in nutrients and have been valued since ancient times.
3. Beans (Phaseolus vulgaris)
   • Origin and Distribution: Native to the New World, beans were domesticated by the Incas and early American Indians. Today, they are grown globally, with significant production in the United States, particularly in Michigan, California, Idaho, and Colorado.
   • Characteristics: Beans are annual plants with varying growth forms including bush or pole types. They have trifoliate leaves, small flowers, and slender pods. There are many varieties, including lima beans, scarlet runner beans, and mung beans.
   • Uses: Beans are used for fresh consumption (string beans), dried seeds (shell beans), and as forage. They are also processed for canning and other products.
4. Cowpeas (Vigna sinensis)
   • Origin and Distribution: Originating from Southeastern Asia, cowpeas have been cultivated for over 2000 years and are now grown in tropical and subtropical regions, including the West Indies and the southern United States.
   • Characteristics: Cowpeas are bushy or trailing annuals with cylindrical, pendant pods. They grow well in warm, humid areas and sandy or loamy soils.
   • Uses: Primarily used as a forage crop and green manure, cowpeas also serve as a food source for cattle and poultry and as a coffee substitute.
5. Soybeans (Glycine soja)
   • Origin and Distribution: Native to Southeastern Asia, soybeans are extensively cultivated in countries like Manchuria, Korea, Japan, and the Dutch East Indies. They have become increasingly important in the United States.
   • Characteristics: Soybeans are bushy, erect, or prostrate annuals. They are notable for their high protein content and are less tangled compared to other legumes.
   • Uses: Soybeans are used in various forms, including soybean oil, soybean milk, and flour. They are essential in the diet of many Far Eastern countries and are gaining importance in the U.S. agriculture.
6. Broad Beans (Vicia faba)
   • Origin and Distribution: Believed to have originated in Algeria or Southwestern Asia, broad beans have been cultivated since prehistoric times. They are still widely grown in the Old World, particularly in England.
   • Characteristics: Broad beans are tall annuals with flat pods and large seeds. They are sensitive to dry, hot summers and are thus less common in North America.
   • Uses: They are used for human consumption, forage, and as a cover crop.
7. Peanuts (Arachis hypogaea)
   • Origin and Distribution: Native to Brazil, peanuts were introduced to the Old World tropics by Portuguese explorers. They were brought to the United States by African slaves and are now a major crop in the southern U.S.
   • Characteristics: Peanuts are bushy or creeping annuals that produce fruit underground. They require warm temperatures and sandy soils.
   • Uses: Peanuts are consumed as roasted nuts, used in candy and peanut butter, and serve as an important food oil. They also provide forage and can improve soil fertility.
8. Lentils (Lens esculenta)
   • Origin and Distribution: Native to Southwestern Asia, lentils were introduced to Greece and Egypt and have historical significance, including mentions in the Bible.
   • Characteristics: Lentils are slender, tufted plants with short pods containing lens-shaped seeds.
   • Uses: Lentils are widely used in soups and are a valuable protein source, often used in place of meat.
9. Cajan Peas (Cajanus cajan)
   • Origin and Distribution: Originally domesticated in Asia or Africa, cajan peas are now cultivated extensively in the tropics, including the East Indies, India, and the West Indies.
   • Characteristics: Cajan peas are erect shrubs with seeds used for both human and animal consumption. They are drought-resistant and adaptable to various soils.
   • Uses: Cajan peas are used as food, forage, and green manure, and are an important crop in many tropical regions.
10. Lablab (Dolichos lablab)
    • Origin and Distribution: Lablab is cultivated in many tropical countries and is known for its woody climbing habit.
    • Characteristics: It produces a high yield of pods over several years and is used for both food and forage.
    • Uses: Both the pods and seeds are consumed, and the plant is used for hay and forage.
11. Horse Beans (Canavalia ensiformis)
    • Origin and Distribution: Native to the West Indies, horse beans are grown in tropical countries and are notable for their hardiness.
    • Characteristics: These are bushy annuals with long pods and large beans.
    • Uses: The seeds are used for human consumption and the plant serves as green forage.
12. Velvet Beans (Stizolobium deeringianum)
    • Origin and Distribution: Velvet beans are widely cultivated in tropical regions for their edible seeds.
    • Characteristics: They are herbaceous climbers with rapid growth.
    • Uses: Velvet beans are used for fodder and are becoming increasingly important in the southern U.S.
13. Kudzu Beans (Pueraria thunbergiana)
    • Origin and Distribution: Native to Japan and Eastern Asia, kudzu beans have been introduced to the United States.
    • Characteristics: Kudzu is a perennial vine that produces hay, forage, and starch from its large roots.
    • Uses: The plant is utilized for hay, forage, and starch extraction.

Forage Legumes Many legumes are cultivated specifically for forage or green manuring rather than human consumption. These include:

• Alfalfa (Medicago sativa)
• Bur Clover (Medicago hispida)
• Bush Clover (Lespedeza striata)
• Medic (Medicago lupulina)
• Sweet Clover (Melilotus alba)
• Vetches (Vicia sativa and V. villosa)
• Clovers: Alsike clover (Trifolium hybridum), Crimson clover (T. incarnatum), Red clover (T. pratense), White clover (T. repens)

Examples of Tree Legumes

Tree legumes are an intriguing subset of the Leguminosae family, offering both nutritional benefits and agricultural advantages. Unlike their herbaceous counterparts, these trees produce edible pods and seeds that can serve as significant food sources and contribute to soil health. This article explores notable examples of tree legumes, highlighting their characteristics, uses, and potential in sustainable agriculture.

1. Algaroba (Prosopis chilensis)

• Origin and Distribution: Native to arid regions of the West Indies, Mexico, and Central America. Introduced to Hawaii, where it now covers approximately 50,000 acres.
• Botanical Characteristics: The algaroba tree is known for its rapid growth and drought resistance. It is capable of thriving on barren, arid land.
• Yield and Uses:
  • Pod Yield: Produces between 2 to 10 tons per acre annually.
  • Nutritional Value: One acre of algaroba can yield 1,600 pounds of beef, significantly outperforming traditional crops like corn and alfalfa in terms of productivity.
  • Applications: The pods and ground beans are utilized as stock feed, and the tree plays a crucial role in soil conservation by preventing erosion.

2. Carob (Ceratonia siliqua)

• Origin and Distribution: Indigenous to Syria and cultivated historically throughout the Mediterranean region.
• Botanical Characteristics: A small evergreen tree with glossy foliage, flowering in autumn and bearing fruit through late summer. It thrives in rocky, dry soils.
• Yield and Uses:
  • Pod Composition: Dried carob pods contain approximately 50% sugar.
  • Historical Significance: Historically, carob pods were a staple food for animals and even for soldiers during historical military campaigns.
  • Modern Applications: The pods are consumed as candy and are used in baking. Carob flour is incorporated into bread, and the seeds are ground to produce a highly nutritious meal. The pods also yield tragasol, a valuable gum.

3. Honey Locust (Gleditsia triacanthos)

• Origin and Distribution: Native to the humid eastern United States, characterized by hot summers and cold winters.
• Botanical Characteristics: Recognizable by its pods containing 29% sugar, the honey locust is both an ornamental and timber tree.
• Yield and Uses:
  • Pod Composition: Pods are high in sugar content and are readily consumed by livestock.
  • Additional Uses: Besides its use as forage, the tree’s timber is valuable, and its ornamental properties enhance landscape aesthetics.

4. Other Notable Tree Legumes

• Mesquite (Prosopis glandulosa):
  • Origin: Southwestern North America, especially arid desert regions.
  • Uses: The pulpy pods have been used as food for both humans and animals.
• Rain Tree (Samanea saman):
  • Origin: Tropical America.
  • Uses: Produces sweet, pulpy pods ideal for stock feed.
• Nittas (Parkia biglobosa and P. filicoidea):
  • Origin: West Africa.
  • Pod Composition: Pods contain 31% sugar, and the seeds yield a nutritious flour with high protein content.
  • Uses: The seeds are a concentrated food source for travelers and natives.
• Inga edulis:
  • Origin: Panama and Peru.
  • Uses: Edible pods with sweet pulp are consumed locally and valued for their agreeable taste.

Economical Importance of Legumes

Legumes are crucial to global economies due to their multifaceted roles in agriculture, food security, and industry. Their economic significance spans various sectors, including agriculture, trade, and nutrition. Here’s a detailed overview:

• Agricultural Significance
  • Crop Rotation and Soil Health: Legumes are integral to crop rotation systems, enhancing soil fertility through nitrogen fixation. This reduces the need for synthetic fertilizers, lowering costs and improving sustainability. For example, clovers and alfalfa are commonly used to replenish soil nitrogen levels, which benefits subsequent crops.
  • Forage and Green Manure: Many legumes, such as alfalfa and clover, are grown primarily as forage for livestock. They provide high-quality feed that supports animal health and productivity. Additionally, legumes like vetches and legumes used as green manure contribute to soil health and structure.
• Economic Value in Food Production
  • Human Consumption: Legumes such as beans, peas, chickpeas, and lentils are staples in diets worldwide due to their high nutritional value and versatility. They are used in various processed forms, including canned goods, frozen products, and snacks. For example, the canning industry for garden peas is a significant economic activity in the United States.
  • Nutritional Benefits: Legumes are a cost-effective source of protein, fiber, and essential nutrients, making them an important dietary component in many developing countries. Their affordability compared to animal proteins makes them crucial for food security.
• Trade and Market Impact
  • Global Trade: Legumes are major export commodities for several countries. For instance, countries like India, Canada, and the United States are significant exporters of pulses. The international trade in legumes supports economies by generating revenue and creating jobs in agriculture and processing industries.
  • Market Demand: The growing global demand for plant-based proteins has increased the market value of legumes. As dietary preferences shift towards vegetarian and vegan options, legumes are gaining prominence in global markets.
• Industrial Uses
  • Oil Production: Soybeans, in particular, are vital in the production of vegetable oils. Soybean oil is used in cooking, food processing, and as a biofuel. The soybean oil industry significantly contributes to the economic output of soybean-growing regions.
  • Biofuels and Industrial Products: Besides oil, legumes contribute to the production of various industrial products, including biodegradable plastics and adhesives. Research into alternative uses continues to expand their economic importance.
• Economic Challenges
  • Price Fluctuations: The prices of legumes can be volatile due to factors such as weather conditions, pests, and global market trends. This volatility can impact farmers’ income and food prices, influencing overall economic stability.
  • Pest and Disease Management: Legumes are susceptible to pests and diseases, which can affect yield and quality. The costs associated with pest management and disease control can impact profitability for growers.