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Your web browser (Safari 7) is out of date. For more security, comfort and the best experience on this site: Update your browser Ignore GRAIN For the complete encyclopedic entry with media resources, visit: http://www.nationalgeographic.org/encyclopedia/grain/ Grain is the harvested seed of grasses such as wheat, oats, rice, and corn. Other important grains include sorghum, millet, rye, and barley. Around the globe, grains, also called cereals, are the most important staple food. Humans get an average of 48 percent of their calories, or food energy, from grains. Grains are also used to feed livestock and to manufacture some cooking oils, fuels, cosmetics, and alcohols. Almost half of the grains grown around the world are harvested for people to eat directly. People turn wheat flour into bread, steam rice, and make corn tortillas. Grains are a food staple in almost every culture on Earth. A food staple is food that is eaten frequently, often at every meal. Staple foods can be eaten fresh or stored for use all year. Rice, corn, and wheat are the most common staple foods on Earth. Grains are so important because they are a good source of important nutrients called carbohydrates. Carbohydrates are a type of sugar that provides energy for organisms to function. Grains have carbohydrates as well as other important nutrients, such as vitamins. While grains fill many nutritional needs, they often lack some important proteins. In many cultures, grains are part of a staple diet when combined with protein-rich legumes, such as beans. Together, grains and legumes make a healthy diet: corn and beans, rice and tofu, wheat bread and peanut butter. A third of the world s grain supply is fed to animals. Most domestic animals, from cattle to dogs, are fed food rich in grains and grain products. 1 of 9

The rest of the world s grain supply is used in the manufacture of industrial products. Biodiesel is a fuel used for vehicles. One type of biodiesel is ethanol, which can be made from corn. Grains are annual plants. This means they have only one growing season per year, yielding one crop. Every growing season, grasses grow, reach maturity, produce seeds, and then die. Grains are harvested from dead, or dry, grasses. Some grains are winter grains, such as rye. They are able to withstand cold, wet climates. Others are summer grains, such as corn. Corn usually grows best in warm weather. Grains can grow in almost any climate. Rice is the most important grain in many tropical areas, where it is hot and humid year-round. Rice is especially common in Asia. In Southeast Asia, rice is grown and harvested in flooded fields called paddies. Rice paddies can be flat or terraced. Terraced rice paddies look like steps on a green hill. This type of grain agriculture has been used for centuries. Unlike rice, sorghum does not grow well in a wet climate. Sorghum favors an arid climate. The nations of West Africa, including Senegal, the Gambia, Burkina Faso, and Cape Verde, are the world s largest producers of sorghum. In temperate areas those with warm summers and cold winters wheat is the most common grain. Wheat fields are common in the Great Plains of the United States and Canada, for instance. Corn, which is native to the Americas, is now grown in many temperate areas throughout the world. Oats, another grain that grows in temperate areas, are also used as a livestock feed. Harvesting Grain People first began eating grains about 75,000 years ago in western Asia. These grains, including einkorn and emmer, were ancestors of today s wheat. Einkorn 2 of 9

and emmer grew wild near the banks of rivers. People harvested the grasses that grew naturally near their communities. People began cultivating, or growing, grain more recently. In 2009, scientists anced that they had discovered the world s oldest known grain silos at Dhra in what is now the nation of Jordan. The silos, which date back 11,000 years, contained remnants of barley and an early type of wheat. Ancient people ate grains in much the same way we do today. Wheat grains were made into flour and used in breads. Rice was steamed and eaten hot or cold. Oats were mashed with water or milk to make oatmeal. Beer, one of the oldest manufactured beverages in the world, is made from grain such as barley. Ancient beers had a very low alcohol content, but were good sources of carbohydrates. In some ancient civilizations, grain products served as wages or forms of currency. Many of the workers who built Egypt s pyramids at Giza, for instance, were often paid in bread and beer. Today, grain silos are a familiar sight to many people in the developed world. Harvesting is done almost entirely with enormous, expensive machinery. The most important piece of agricultural machinery for grain crops is the combine harvester. This remarkable machine does three jobs: it cuts the grain, threshes the grain, and winnows the grain. Cutting, of course, is removing the grain from the stalk of grass. Threshing is loosening the edible grain from its casing, called the chaff. (Chaff is inedible; organisms cannot digest it.) Winnowing is the process of removing the grain from the chaff. Combine harvesters help farmers expand the amount of grains they can harvest by combining three activities into one. In the developing world, few farmers have the huge fields of grain that agribusinesses in the developed world do. Farmers in the developing world typically have a few acres, and provide grain for their local community. These 3 of 9

farmers usually thresh and winnow with separate machines (threshers and winnowers) after harvesting the field. In many places, harvesting is still done with hand tools such as the sickle, a long, curved blade used for cutting many stalks of grain at once. Vocabulary Term acre unit of measure equal to.4 hectares. agribusiness agriculture alcohol the strategy of applying profit-making practices to the operation of farms and ranches. the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching). chemical compound, usually ethanol or methanol, generated by fermentation and used for fuel, hygiene, medicine, and food. ancestor organism from whom one is descended. ancient annual arid bank adjectivevery old. adjectiveyearly. adjectivedry. a slope of land adjoining a body of water, or a large elevated area of the sea floor. barley grass cultivated as a grain. bean edible seed of legumes. beer alcoholic beverage made from grain. beverage liquid for drinking. biodiesel calorie fuel made at least partly from renewable sources such as soy oil, palm oil, or animal fats. unit of energy from food, equal to the amount of heat required to raise the temperature of one kilogram of water by one degree Celsius. 4 of 9

Term carbohydrate type of sugar that is an important nutrient for most organisms. casing material on the outside of a substance, usually there to protect the material inside. cattle cows and oxen. cereal type of grain, including wheat. chaff the dry, usually worthless, husks of grain or grass. civilization complex way of life that developed as humans began to develop urban settlements. climate all weather conditions for a given location over a period of time. combine harvester farm machine that cuts, threshes, and winnows grain. cooking oil liquid fat taken from plants such as olives and soy. Also called vegetable oil. corn, tall cereal plant with large seeds (kernels) cultivated for adjective food and industry. Also called maize. cosmetics substances applied to the body to make it appear more attractive. cultivate verb to encourage the growth of something through work and attention. culture learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods. currency money or other resource that can be used to buy goods and services. developing nations with low per-capita income, little infrastructure, world and a small middle class. diet foods eaten by a specific group of people or other organisms. 5 of 9

Term digest verb to convert food into nutrients that can be absorbed. discover verb to learn or understand something for the first time. domestic animal animal that has been tamed for work or to be a pet. edible adjectiveable to be eaten and digested. einkorn type of wheat. emmer type of wheat. energy capacity to do work. enormous adjectivevery large. ethanol type of grain alcohol used as biofuel. expensive adjectivevery costly. familiar adjectivewell-known. feed processed food for livestock. flour ground grain, usually of wheat. food material, usually of plant or animal origin, that living organisms use to obtain nutrients. food staple food that is eaten frequently, either fresh or stored for use all year. frequent adjectiveoften. fuel material that provides power or energy. grain harvested seed of such grasses as wheat, oats, and rice. grain large storage facility for grains, equipped with lifting elevator mechanisms. grain silo large storage facility for grains. grass type of plant with narrow leaves. Great Plains grassland region of North America, between the Rocky Mountains and the Mississippi River. growing period in the year when crops and other plants grow season rapidly. 6 of 9

Term harvest the gathering and collection of crops, including both plants and animals. humid adjectivecontaining a large amount of water vapor. inedible adjectivenot able to be eaten or digested. legume type of plant with a pod that splits, with seeds in the middle, such as peanuts. livestock, plural animals raised for sale and profit. machinery mechanical appliances or tools used in manufacturing. maize corn. manufacture verb to make or produce a good, usually for sale. millet, a type of grain. adjective nutrient substance an organism needs for energy, growth, and life. oatmeal rolled or ground oats mixed with water or milk. oats type of edible grass. protein one of many complex compounds, made of chains of amino acids, that make up the majority of all cellular structures and are necessary for biological processes. raw material matter that needs to be processed into a product to use or sell. remarkable adjectiveunusual and dramatic. remnant something that is left over. rice grass cultivated for its seeds. rice paddy rice field. river large stream of flowing fresh water. rye cereal grain grown for food. seed part of a plant from which a new plant grows. 7 of 9

Term sickle long, curved blade attached to a handle, used for cutting many stalks of grass at once. sorghum type of grain. stalk stem of a plant. steam verb to heat something by placing it over boiling water. sugar type of chemical compound that is sweet-tasting and in some form essential to life. summer grain grass that is harvested during the summer or autumn. temperate adjectivemoderate. terrace flat surface created on a steep hillside. thresh verb to loosen the grain from its casing, called chaff. tofu thick, soft substance of varying consistency made from soybeans. tortilla flat, round bread made from corn or flour. existing in the tropics, the latitudes between the Tropic of tropical adjective Cancer in the north and the Tropic of Capricorn in the south. vehicle device used for transportation. vitamin chemical substance that is necessary for health. wage money or goods traded for work or service performed. weather state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness. wheat most widely grown cereal in the world. winnow verb to separate the grain from the inedible casing, called chaff. winter grain grass that is harvested during the winter or spring. yield verb to produce or result in. Articles & Profiles 8 of 9