• crop
    Grains, such as the sorghum these farmers are carrying, are the most popular food crop.

    Photograph by W. Robert Moore

    Most Popular Crops: U.S.
    1. Corn
    2. Soy
    3. Hay
    4. Wheat
    5. Cotton

    Crop of Crops

    • break crop: lesser-value crop planted in the process of crop rotation
    • bumper crop: harvest that has resulted in an unusually large or profitable amount of produce
    • cash crop: crop that is grown for sale
    • catch crop: fast-growing secondary crop that is grown between plantings of a larger crop
    • cover crop: crop planted to maintain soil quality more than agricultural produce
    • nurse crop: crop of an annual species grown to help establish a crop of a perennial species
    • permanent crop: crops from annual plants, which don't have to be re-planted every year

    A crop is a plant or plant product that can be grown and harvested for profit or subsistence. By use, crops fall into six categories: food crops, feed crops, fiber crops, oil crops, ornamental crops, and industrial crops.

    Food crops, such as fruit and vegetables, are harvested for human consumption. Grains, such as corn, wheat, and rice, are the world’s most popular food crops.

    Food crops were the first crops to be harvested through agriculture. Agricultural development and the growth of civilizations led to the diversity of other types of crops.

    Feed Crops

    Feed crops, such as oats and alfalfa, are harvested for livestock consumption. These crops contain nutrients that animals need to develop. They are grown in agricultural fields but can also be found in natural meadows and pastures.

    The most popular type of feed crop is a forage crop. Animals feed directly on forages, such as grasses. Forages that are cut and fed to livestock while they are still fresh are called green chop. Alfalfa is a popular crop fed to livestock as green chop.

    Some forages are cut, allowed to dry in the field, and stored. These are called hay crops.

    Another type of forage crop is silage. Silage crops are harvested, then stored under conditions that allow the forage to break down (ferment) into acids. The wet, acidic silage is fed to livestock such as cattle.

    Principle feed crops include corn, barley, wheat, and oats. Each of these crops has different properties that are better suited for some animals’ diets over others. Barley, which is harder to digest, is most often fed to beef and dairy cattle because they have a tough, four-chambered stomach. Hull-less barley, which is easier to digest, is fed to swine and poultry.

    The production of feed crops has risen dramatically with increased demand for meat worldwide. Increased production of feed crops has changed the agricultural landscape.

    The Food and Agriculture Organization (FAO) says 33 percent of arable land on Earth is used to produce food for livestock. This limits the production of crops for human consumption, especially for the world’s poorest people. Feed crops and grazing pastures disturb natural water cycles, drawing away water from underground aquifers that provide the earth with a constant and balanced supply of water.

    Forests have been cleared to create pastures where livestock can graze. Almost 70 percent of land cleared from the Amazon rain forest, for instance, has been turned over to grazing.

    Fiber Crops


    Fiber crops, such as cotton and hemp, are harvested for textile and paper products. Textiles, or cloth, are made from the dried and processed fibers of certain plants. Most fibers used to make textiles are taken from the stem or roots of plants such as flax. Flax is used to make linen.

    Other parts of a plant can be harvested for fiber. Cotton, the most popular fiber crop in the world, is harvested from the light, fluffy “boll” of fiber that surrounds the plant’s seeds. Textiles made from bamboo are manufactured from the pulp of bamboo plants.

    Pulp from other fiber crops can be used in a variety of products. Fiber pulp may be used instead of wood pulp to manufacture paper products.

    The hemp plant is an interesting and controversial example of a fiber crop. The fibers of the hemp plant are strong and durable, perfect for products such as paper, textiles, ropes, nets, and sailcloth for ships. Hemp advocates see the plant as a versatile and ecological source of fiber.


    But some varieties of the hemp plant are used to make marijuana, a narcotic drug. Marijuana is illegal to grow and use in most parts of the United States. (The drug is legally grown and sold for medical use in some places.) Opponents of hemp argue that increased harvesting of hemp crops will lead to increased production and use of marijuana.

    Oil Crops


    Oil crops, such as canola and corn, are harvested for consumption or industrial uses. Technologies developed in the past century have enabled crops to be processed and broken down into their primary components, including oil. Soybeans, for example, represented 56 percent of world oilseed production and 79 percent of all edible oil consumed in the United States in 2000.

    Oil crops are harvested for use in cooking, such as olive oil and corn oil. Oil crops are also harvested for industrial use, such as oil paints, soaps, and lubrication for machinery.

    Fuel made from oil crops is called biofuel. The demand for biofuels has grown in recent years. Rising gas prices, concerns about global warming, and a desire for energy self-sufficiency have led governments and businesses to invest in biofuel research.

    There are two main types of biofuel that use oil crops: bioethanol and biodiesel.

    Bioethanol is an alcohol made from fermented materials that come from sugar and starch crops. These crops include sugar cane, corn, and wheat. Bioethanol can be used as a fuel for vehicles, but it is usually used as a gasoline additive to improve vehicle emissions. Bioethanol is used widely in the United States and Brazil, where an abundance of corn and sugar cane crops facilitate its production.

    Biodiesel is made by combining vegetable oils with alcohol. Nuts, such as coconuts, macadamias, and pecans, are excellent sources of oil used to manufacture biodiesel. Biodiesel can be used in diesel engines, such as those used by buses. Brazil, the United States, and the European Union (particularly Germany) manufacture and use biodiesel on a large scale.

    Biofuels provide almost 2 percent of the world’s transport fuel. Many scientists and economists predict that number will rise as oil production decreases in the next century.

    Ornamental Crops


    Ornamental crops, such as dogwood and azalea, are harvested for landscape gardening. Ornamental crops are most often grown in nurseries, where they are purchased for residential or commercial settings.

    Ornamental crop production has deep historical roots. The tulip crop of the Netherlands, for example, has become a symbol of that country.

    Today, ornamental crop production is an important economic activity in many developing countries. Kenya, for example, is a major exporter of roses and carnations. Kenyan flower growers have situated their greenhouses near the shores of Lake Naivasha and Lake Victoria, where the soil is fertile and the water is abundant and fresh.

    Kenya’s huge flower operations, however, are having a negative impact on lake ecosystems. Growers irrigate their flowers with lake water, dramatically lowering supplies of freshwater available for consumption and hygiene. Growers also apply heavy amounts of fertilizers and pesticides so their flowers can maintain their beauty throughout the export process. These chemicals often runoff into the lakes, endangering aquatic animal and plant life.

    Industrial Crops

    Industrial crops, such as rubber and tobacco, are harvested for their products’ use in factories or machines. Industrial crops include all crops used in the production of industrial goods, such as fiber and fuel products.


    Rubber is produced naturally from a wide variety of plants, but predominantly from the Hevea tree indigenous to Brazil. Rubber is harvested for its latex. Latex is an extremely tough fluid found in the inner bark of the Hevea tree. Latex is obtained by tapping—cutting or shaving the bark with a sharp knife—and collecting the latex in cups. When mixed with chemicals, latex creates solid rubber blobs, called curds. Rubber curds are pressed between rollers to remove excess moisture and to form sheets. The sheets are packed and shipped for use in tires, machine belts, shoe soles, and other products.

    Rubber has been used by civilizations for thousands of years. One of the earliest uses of rubber was to create balls for use in games in the Olmec Empire in what is today Mexico. Today, rubber is still used to manufacture durable toys, as well as boots, flooring, balloons, and medical supplies.

    Hevea trees transplanted to southern Asia now produce most of the world’s rubber. The countries with the largest rubber crops are Thailand, Indonesia, and Malaysia. Industrialization around the world has increased the global demand for rubber. High demand for natural rubber has increased the environmental degradation of forests in southern Asia.

    Harvesting Crops

    Methods for growing and harvesting crops have developed over thousands of years. The earliest crops were grown in Mesopotamia around 5500 BCE. These crops, indigenous to an agriculturally rich area called the Fertile Crescent, were grown near local sources of freshwater so they could be irrigated relatively easily. Wheat, barley, and figs were among the first crops.

    The development of agriculture led to more sophisticated methods of harvesting crops. Crop rotation was the most significant innovation. In crop rotation, one crop is planted one year, then a different crop is planted the next year on the same land. This helps preserve the soil and reduce the chance for disease.

    Crop rotation and fertilization, which makes soil more productive, allowed farmers to grow more crops on less land. These innovations also allowed crops to be grown in areas where they might not grow naturally. Improved engineering allowed rivers to be dammed and diverted to provide water for crops. All of these developments increased the abundance of crops, which could be used for trade and industrial use.

    Today, agriculture is the largest industry in the world. Millions of people harvest crops for subsistence or business purposes. Some tools used to harvest crops have not changed in a thousand years—plows, rakes, sickles. Most of all, harvesting crops still relies on human labor.

    The tools and machinery used to harvest crops have grown much more complex and expensive, however. Fertilizers, which many farmers need to be economically competitive, cost more than many farmers in the developing world can afford. Machinery, such as tractors and plows, can cost hundreds of thousands of dollars.

    GMOs


    Technological and biological advancements in agriculture—such as chemical pesticides and fertilizers—have increased crop growth and resilience while they have decreased crop losses and prices.

    Genetically modified organisms (GMOs or GM foods) are common throughout the developed world. Biotechnology allows scientists to alter the DNA of microbes, plants, and animals. Businesses sell farmers genetically modified seeds. With these seeds, farmers can use toxic chemicals without harming the crop. Farmers who grow GM foods increase production with less labor and less land. Vegetables and fruits last longer and are less likely to bruise.

    The heavy reliance on chemicals has disturbed the natural environment, however. Helpful species of animals may be killed along with harmful ones. Chemical use may also pose a health hazard to people, especially through runoff entering local aquifers and other water supplies. Critics argue that GM foods have less nutritional value and decrease biodiversity.

    Organic and free-range food industries have grown in opposition to industrial farming. Agricultural scientists are looking for safer chemicals to use as fertilizers and pesticides. Some farmers use natural controls and rely less on chemicals.

    Seed Banks

    In order to preserve biodiversity, seed banks have been created around the world to store seed samples. Seed banks may specialize in a specific crop or in the crops of a region. The International Potato Center, based in Lima, Peru, houses 150 wild potato species and other tubers of Andean origin.

    Native Seeds, founded in the southwestern United States, helps Native Americans locate seeds for growing traditional crops, such as orach, or “mountain spinach,” and amaranth, once widely used for food and fiber in Mexico.

    The Svalbard Global Seed Vault, the world’s most diverse seed bank, was established in 2008. The Norwegian government built the Seed Vault into the side of a permafrost-covered mountain on the island of Spitsbergen, part of the Svalbard archipelago about 1,030 kilometers (620 miles) from the North Pole. The vault is designed to safely store the seeds of hundreds of thousands of plant varieties from crops grown throughout the globe. The Seed Vault offers “fail-safe” protection for the world’s agricultural inheritance against any natural, social, or economic disaster.

    Today, the Seed Vault stores about 420,000 seed samples. It has the capacity to hold 4.5 million samples.

    Crops have a wide variety of uses and are an integral part of our existence and development. While advancements in crop science and technology have increased the production of some of our most basic foodstuffs, they also have had wide-ranging impacts on the environment.

    The production of crops does not have to harm the environment. By protecting the land, water, and air, and by sharing knowledge and resources, people may find solutions for the problems of world hunger and global energy scarcities through the sustainable use of crops.

  • Term Part of Speech Definition Encyclopedic Entry
    abundance Noun

    large amount.

    abundant Adjective

    in large amounts.

    acid Noun

    chemical compound that reacts with a base to form a salt. Acids can corrode some natural materials. Acids have pH levels lower than 7.

    advocate Verb

    to argue in favor of something.

    agricultural development Noun

    modern farming methods that include mechanical, chemical, engineering and technological methods. Also called industrial agriculture.

    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    alcohol Noun

    chemical compound, usually ethanol or methanol, generated by fermentation and used for fuel, hygiene, medicine, and food.

    alfalfa Noun

    legume that is often used as feed for livestock.

    alter Verb

    to change.

    amaranth Noun

    plant cultivated for flowers and food.

    aquatic Adjective

    having to do with water.

    aquifer Noun

    an underground layer of rock or earth which holds groundwater.

    Encyclopedic Entry: aquifer
    arable Adjective

    land able to produce crops.

    archipelago Noun

    a group of closely scattered islands in a large body of water.

    Encyclopedic Entry: archipelago
    bamboo Noun

    type of huge, woody grass.

    bark Noun

    typically hard, outer covering of a tree.

    barley Noun

    grass cultivated as a grain.

    beef Noun

    flesh of a cow used for food.

    biodiesel Noun

    fuel made at least partly from renewable sources such as soy oil, palm oil, or animal fats.

    biodiversity Noun

    all the different kinds of living organisms within a given area.

    Encyclopedic Entry: biodiversity
    bioethanol Noun

    alcohol made from fermented materials that come from sugar and starch crops.

    biofuel Noun

    energy source derived directly from organic matter, such as plants.

    biotechnology Noun

    the use of a living organism for industrial or medical use.

    boll Noun

    pod that carries the seeds of certain plants, such as cotton.

    capacity Noun

    ability.

    cattle Noun

    cows and oxen.

    civilization Noun

    complex way of life that developed as humans began to develop urban settlements.

    Encyclopedic Entry: civilization
    commercial Adjective

    having to do with the buying and selling of goods and services.

    complex Adjective

    complicated.

    component Noun

    part.

    controversial Noun

    questionable or leading to argument.

    cotton Noun

    cloth made from fibers of the cotton plant.

    crop Noun

    agricultural produce.

    Encyclopedic Entry: crop
    crop rotation Noun

    the system of changing the type of crop in a field over time, mainly to preserve the productivity of the soil.

    crop science Noun

    research to enhance agricultural productivity while sustaining the integrity of ecological processes.

    dairy Adjective

    having to do with the production of milk, cream, butter, or cheese.

    dam Verb

    to block a flow of water.

    degradation Noun

    breaking down.

    developing world Noun

    nations with low per-capita income, little infrastructure, and a small middle class.

    diesel Noun

    oil or other fuel used in diesel engines, emitting a low, constant temperature.

    diet Noun

    foods eaten by a specific group of people or other organisms.

    Encyclopedic Entry: diet
    digest Verb

    to convert food into nutrients that can be absorbed.

    disaster Noun

    terrible and damaging event.

    disease Noun

    a harmful condition of a body part or organ.

    diversity Noun

    difference.

    divert Verb

    to direct away from a familiar path.

    DNA Noun

    (deoxyribonucleic acid) molecule in every living organism that contains specific genetic information on that organism.

    drug Noun

    chemical substance used to change the physical or mental state of an organism.

    durable Adjective

    strong and long-lasting.

    economic Adjective

    having to do with money.

    economically competitive Adjective

    able to buy and sell goods and services without significant government or private aid.

    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    edible Adjective

    able to be eaten and digested.

    emission Noun

    discharge or release.

    energy Noun

    capacity to do work.

    engineering Noun

    the art and science of building, maintaining, moving, and demolishing structures.

    establish Verb

    to form or officially organize.

    European Union Noun

    association of European nations promoting free trade, ease of transportation, and cultural and political links.

    expensive Adjective

    very costly.

    facilitate Verb

    to help or make easier.

    fail-safe Adjective

    completely reliable.

    feed crop Noun

    plants grown and harvested for livestock or other animal consumption.

    ferment Verb

    to undergo the natural or artificial process of fermentation, or changing a food's sugars into alcohols.

    fertile Adjective

    able to produce crops or sustain agriculture.

    Fertile Crescent Noun

    region extending from the eastern Mediterranean coast through Southwest Asia to the Persian Gulf.

    fertilizer Noun

    nutrient-rich chemical substance (natural or manmade) applied to soil to encourage plant growth.

    fiber Noun

    long, thin, threadlike material produced by plants that aids digestive motion when consumed.

    fiber crop Noun

    plants grown and harvested for use in making textile and paper products.

    flax Noun

    plant cultivated for its oil, seeds, and fibers, used to make linen. Also called linseed.

    food Noun

    material, usually of plant or animal origin, that living organisms use to obtain nutrients.

    Encyclopedic Entry: food
    Food and Agriculture Organization (FAO) Noun

    United Nations agency responsible for improving food production in developing countries.

    food crop Noun

    plants grown and harvested for human consumption.

    foodstuff Noun

    food or ingredients used to make food.

    forage Verb

    to search for food or other needs.

    forest Noun

    ecosystem filled with trees and underbrush.

    free-range Adjective

    having to do with livestock or poultry that have been allowed to graze instead of being fed on a feed lot.

    freshwater Noun

    water that is not salty.

    fruit Noun

    edible part of a plant that grows from a flower.

    fuel Noun

    material that provides power or energy.

    gasoline Noun

    liquid mixture made from oil and used to run many motor vehicles.

    genetically modified organism (GMO) Noun

    living thing whose genes (DNA) have been altered for a specific purpose.

    global warming Noun

    increase in the average temperature of the Earth's air and oceans.

    Encyclopedic Entry: global warming
    government Noun

    system or order of a nation, state, or other political unit.

    grain Noun

    harvested seed of such grasses as wheat, oats, and rice.

    Encyclopedic Entry: grain
    grass Noun

    type of plant with narrow leaves.

    graze Verb

    to feed on grass, usually over a wide pasture.

    green chop Noun

    feed crops that are cut and fed to livestock while they are still fresh.

    greenhouse Noun

    building, often made of glass or other clear material, used to help plants grow.

    harvest Noun

    the gathering and collection of crops, including both plants and animals.

    hay crop Noun

    feed crops that are cut, allowed to dry in the field, and then stored.

    hazard Noun

    danger or risk.

    hemp Noun

    fiber from the hemp plant used for making rope and cloth.

    hull Noun

    the outer covering of a seed or fruit.

    hunger Noun

    the need for food.

    hygiene Noun

    science and methods of keeping clean and healthy.

    illegal Adjective

    forbidden by law.

    indigenous Adjective

    native to or characteristic of a specific place.

    industrial Adjective

    having to do with factories or mechanical production.

    industrial crop Noun

    plants grown and harvested for use in making products, rather than for food.

    industrialization Noun

    growth of machine production and factories.

    inherit Verb

    to receive from ancestors.

    innovation Noun

    something new.

    integral Adjective

    very important.

    irrigate Verb

    to water.

    island Noun

    body of land surrounded by water.

    Encyclopedic Entry: island
    labor Noun

    work or employment.

    lake Noun

    body of water surrounded by land.

    landscape Noun

    the geographic features of a region.

    Encyclopedic Entry: landscape
    latex Noun

    liquid found in some plants that clumps when exposed to air and certain chemicals, used to make rubber.

    linen Noun

    light, thin, durable fabric made from fibers of the flax plant.

    livestock noun, plural noun

    animals raised for sale and profit.

    lubricate Verb

    to apply with grease or oil.

    machinery Noun

    mechanical appliances or tools used in manufacturing.

    manufacture Verb

    to make or produce a good, usually for sale.

    marijuana Noun

    dried leaves of the female flowers of the hemp plant, used as a narcotic.

    meadow Noun

    wide area of grassland.

    Mesopotamia Noun

    area between the Tigris and Euphrates River in Iraq.

    microbe Noun

    tiny organism, usually a bacterium.

    narcotic Noun

    chemical substance that dulls or soothes the senses when it enters the bloodstream.

    Native American Noun

    person whose ancestors were native inhabitants of North or South America. Native American usually does not include Eskimo or Hawaiian people.

    North Pole Noun

    fixed point that, along with the South Pole, forms the axis on which the Earth spins.

    Encyclopedic Entry: North Pole
    nutrient Noun

    substance an organism needs for energy, growth, and life.

    Encyclopedic Entry: nutrient
    oil crop Noun

    plants grown and harvested to be processed and broken down into solids and oils, and the oils used for food or industrial purposes.

    oilseed Noun

    seed from which oil can be drawn, such as sesame or cotton.

    Olmec Noun

    people and culture native to Mexico's Gulf coast.

    orach Noun

    leafy green plant eaten as a vegetable, similar to spinach. Also called Atriplex and saltbush.

    organic Adjective

    produced according to standards using limited amounts of chemical additives.

    ornamental crop Noun

    plants grown and harvested for landscape gardening.

    pasture Noun

    type of agricultural land used for grazing livestock.

    permafrost Noun

    permanently frozen layer of the Earth's surface.

    Encyclopedic Entry: permafrost
    pesticide Noun

    natural or manufactured substance used to kill organisms that threaten agriculture or are undesirable. Pesticides can be fungicides (which kill harmful fungi), insecticides (which kill harmful insects), herbicides (which kill harmful plants), or rodenticides (which kill harmful rodents.)

    plant Noun

    organism that produces its own food through photosynthesis and whose cells have walls.

    plow noun, verb

    tool used for cutting, lifting, and turning the soil in preparation for planting.

    potato Noun

    plant native to the Americas.

    poultry Noun

    domesticated birds, such as chickens.

    predominant Adjective

    leading or most influential.

    preserve Verb

    to maintain and keep safe from damage.

    principle Noun

    rule or standard.

    profit Noun

    money earned after production costs and taxes are subtracted.

    pulp Noun

    moist wood fibers from which paper is made.

    rain forest Noun

    area of tall evergreen trees and a high amount of rainfall.

    reliance Noun

    dependence.

    resilient Adjective

    able to recover.

    resource Noun

    available supply of materials, goods, or services. Resources can be natural or human.

    root Noun

    part of a plant that secures it in the soil, obtains water and nutrients, and often stores food made by leaves.

    rubber Noun

    natural or man-made chemical substance that is tough, elastic and can resist moisture.

    rubber curd Noun

    solid material formed when certain chemicals mix with natural latex. Curds are used to make rubber.

    runoff Noun

    overflow of fluid from a farm or industrial factory.

    Encyclopedic Entry: runoff
    sailcloth Noun

    fabric, usually cotton or nylon, used for making boat sails.

    seed Noun

    part of a plant from which a new plant grows.

    seed bank Noun

    collection of seeds, preserved in case other specimens are destroyed.

    self-sufficient Adjective

    able to support all of one's basic needs without assistance.

    shore Noun

    coast.

    sickle Noun

    long, curved blade attached to a handle, used for cutting many stalks of grass at once.

    significant Adjective

    important or impressive.

    silage Noun

    feed crops that are harvested and preserved through fermentation.

    situate Verb

    to place or arrange.

    sophisticated Adjective

    knowledgeable or complex.

    soy Noun

    beans, or fruit, of the soybean plant, native to Asia.

    specific Adjective

    exact or precise.

    starch Noun

    carbohydrate found in many vegetables and cereals.

    stem Noun

    main stalk of a plant.

    subsistence agriculture Noun

    type of agriculture in which farmers grow crops or raise livestock for personal consumption, not sale.

    sugar Noun

    type of chemical compound that is sweet-tasting and in some form essential to life.

    sustainable Adjective

    able to be continued at the same rate for a long period of time.

    sustainable agriculture Noun

    processes for growing crops and raising livestock that makes the most efficient use of resources. Sustainable agriculture aims to cultivate the land so it may be used by future generations.

    Svalbard Global Seed Vault Noun

    large seed bank in Spitsbergen, Norway.

    swine Plural Noun

    (singular: swine) pigs or hogs.

    tapping Verb

    to cut into a tree in order to draw sap or another fluid from it.

    technology Noun

    the science of using tools and complex machines to make human life easier or more profitable.

    textile Noun

    cloth or other woven fabric.

    toxic Adjective

    poisonous.

    tractor Noun

    agricultural vehicle used for moving and operating heavy machinery.

    trade Noun

    buying, selling, or exchanging of goods and services.

    transport Verb

    to move material from one place to another.

    tuber Noun

    thick part of an underground stem of a plant, such as a potato.

    tulip Noun

    colorful, cup-shaped flower native to Asia.

    vegetable Noun

    plant that is grown or harvested for food.

    versatile Adjective

    able to adjust to different conditions.

    water cycle Noun

    movement of water between atmosphere, land, and ocean.

    Encyclopedic Entry: water cycle
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