Agriculture involves raising deliberately bred crops and livestock (see \Tanimal husbandry\t) for food, fiber, and other materials. Although thousands of plant and animal species exist, only 200 plant and about 50 animal species have been domesticated. About 12 or 13 plant crops are important staples, and almost all of these are \Lgrain\ls--especially wheat, rice, and maize (corn)--that were domesticated from wild \LGrasse\ls by deliberate cultivation of their seeds. During the \TPaleolithic Period\t--from at least 2.5 million years ago to about 8000 BC--people hunted, fished, or gathered their food (see \Tprehistoric humans\t). From about 11,000 to 8000 BC, flint-edged wooden sickles were used to gather wild grains, which were stored in caves; about 9000 BC, sheep were domesticated in the Near East. From approximately 8300 to 6500 BC, during the \TMesolithic Period\t, groups of people began to practice natural plant husbandry by simply broadcasting seeds and waiting for the harvest. The only crude tool needed was a haft of bone, wood, or antler fitted with a microlith--a small, sharp blade of stone--for reaping grain. Dogs were the first animals to be tamed, usually to help in hunting. In the Near East such herd animals as goats, sheep, and cattle were domesticated. The practice of cultivating plants became established in the Near Eat and Europe about 6500-3500 BC, in southeast Asia about 6800-4000 BC, and in Mesoamerica and Peru about 2500 BC. Most areas where cultivation began were located in river valleys having semiarid climates. The process of cultivation in the Old World (see \TNeolithic Period\t) involved preparing soil by harrowing--breaking down and smoothing with a tree branch--and sowing choice seeds with a stick plow. In Mesoamerica, where no species of draft animal existed and where the chief grain--maize--required individual planting, a plowless form of cultivation developed, whereby a digging stick was used to make holes into which the seeds were dropped. Early Agriculture in the Old World The evolution from nomadic \Thunter-gatherers\t to cultivators allowed people to establish permanent villages because they had a reliable food supply close at hand. More people were freed from providing food and were able to develop technologies and services that led to the shift from farming communities to towns; eventually, agriculture-based civilizations were formed. In \TMesopotamia\t, the region between the Tigris and Euphrates rivers in present-day Iraq (see \TFertile Crescent\t), cultivation began in the 9th millennium BC. The wheel was invented, pulleys were used to draw water from artificial canals, and complex \Tirrigation\t systems were constructed. Mesopotamians raised wheat and other cereal grains; were skilled in gardening; and domesticated the camel, donkey, and horse. Relying on the water and fertile silt of the Nile, Egyptians (see \TEgypt, ancient\t) irrigated land to ensure large crops of wheat and barley, which, along with flax, provided the basis for their agriculture. Several types of palm trees were cultivated, and wild papyrus was harvested to make paper. In addition to oxen and horses, the Egyptians kept poultry, sheep, goats, swine, and cattle. The \TIndus civilization\t of northern India, which existed from about 2300 to 1750 BC, raised wheat, barley, and rice. These people grew such plants as cotton, sesame, tea, and sugarcane. Chickens were domesticated from Indian jungle fowl, and the water buffalo and zebu cattle were used as draft animals. Farmers used plows, designed effective irrigation systems, and built large granaries. Among the river valleys of China, people learned how to cultivate soybeans, oranges, peaches, pears, hemp, and tea. They kept livestock, practiced intensive gardening, and excelled at flower horticulture. Agriculture in Pre-Columbian America In Mesoamerica--what is now Mexico and Central America--gourds, peppers, avocados, and a grain, amaranth, were domesticated from 7000 to 5000 BC. The people of Mesoamerica were nomadic hunters and semiagriculturists, however, until 2500 BC, when maize was domesticated. The Maya-Toltec-Aztec civilization flourished in Mexico and Central America from AD 250 to 1600 (see \TAztec\t; \TMaya\t). These people hybridized corn to increase yields and also cultivated beans, squash, chili peppers, avocados, and potatoes. They grew tobacco and several species of cotton. They built irrigation canals and made artificial gardens that floated on water, such as those seen at \TXochimilco\t. Dry farming--cultivation of nonirrigated lands by moisture-retaining tillage--was practiced. At about AD 1200 the \TInca\t were carving out an empire in the Andes amid a harsh environment. They used stone hoes and digging sticks with a foot rest for pushing the end into the soil. Terraces, irrigation, and drainage systems were constructed skillfully; land was fertilized, and stone storehouses were built to preserve food. The Inca cultivated such foods as corn, white and sweet potatoes, and squash. They domesticated the llama as a beast of burden and kept alpacas for wool. Early Greece and Rome From 2000 BC on, the Greeks cultivated cereal grains--chiefly barley--raised olive and fig trees, and kept vineyards and livestock. The Greeks are credited with inventing a water wheel equipped with buckets to raise water to a higher level. Farmers used wooden implements primarily, including a threshing sledge with rocks for teeth. The Romans advanced farm technology in the Mediterranean world by making tools, including the plow, reaper, hoe, and sickle, that had iron parts. They cultivated wheat, barley, and millet, kept vineyards, and raised livestock. Before 200 BC, Roman farmers were independent, each owning about 1.8 to 6.1 ha (4 to 15 acres). During the next 200 years the wealthy acquired publicly owned lands until they each controlled hundreds or thousands of hectares, which were worked by slaves. Throughout this period a series of agrarian laws were enacted to divide land held by the wealthy and distribute it to small farmers. These attempts at land reform eventually failed, and by AD 200 many farmers were tenants on estates. By AD 400 the rights of these tenants were reduced until they became serfs, bound to the land. Medieval Europe Farmers who did own small holdings divided their land among their sons. The subsequent small holdings ensured poverty among independent farmers, and especially after the Roman Empire collapsed in AD 476, small farmers were forced to surrender their lands to powerful nobles in return for protection. This arrangement evolved during the High \TMiddle Ages\t (AD 1000-1300) into \Tmanorialism\t, especially in England, France, and Germany. Under manorialism, serfs lived in villages near the lord's manor and farmed their own plots in open, commonly held fields as well as laboring on the lord's land, or demesne. Each serf farmed 5 to 12 ha (12 to 30 acres), which were divided into 0.4-ha (1-acre) strips and scattered throughout three fields among the holdings of other serfs. One field remained fallow for a year in order to rejuvenate its fertility. Such crops as wheat, barley, beans, oats, and rye were planted in the other fields. Similar manorial systems developed in China, Japan, and India. Enclosure and the Agricultural Revolution During the 15th century the owners of English landed estates began to enclose their lands with hedges (see \Tenclosure\t). The first enclosure movement (1485-1603) converted arable land to pasture for sheep. Enclosure movements of the 1600s and especially from 1750 to 1831 permitted holders to cultivate large sections of land with the same crop. This procedure was more efficient than farming strips, eliminated the practice of letting land lie fallow, and allowed farmers to experiment with crop rotation and other agricultural technologies. Enclosure of lands, however, served to displace farmers, who either became tenants or landless farm laborers or migrated into the growing cities (see \TIndustrial Revolution\t). Other European countries slowly began to enclose lands after 1800. The invention of mechanical farm implements during the 17th and 18th centuries created an agricultural revolution in England. The inventions included Joseph Boyce's \Treaper\t (1799) and Jethro \TTull\t's horse-drawn drill (1701). Charles, 2d Viscount \TTownshend\t, of Norfolk introduced crop rotation of clover, wheat, turnips, and barley--an alternation of grain crops with nitrogen-fixing legumes and grasses that put nutrients back into the soil. Such \Lfertilizer\ls as guano, lime, gypsum, and sandy clay, known as marl, were used to improve the soil. The first agricultural society (founded 1793) included Arthur Young (1741-1820), an educator who spread English agricultural innovations to the rest of Europe and the United States. In France during this period (1756-70) a group of men called \Tphysiocrats\t--notably Francois Quesnay and Pierre Samuel du Pont de Nemours (see \Tdu Pont\t family)--began to outline agricultural economics. With the age of colonialism, the European powers established plantations throughout Africa, Asia, the Pacific, the Caribbean, and Latin America. On these large land holdings, such cash crops as coffee, tea, bananas, and rubber were introduced, and indigenous people worked as wage laborers. Colonial America Throughout the coastal colonies settlers were taught by native Americans how to plant corn and other indigenous crops. In Canada during the 1700s mainly fur trappers and only a few farmers in Quebec occupied the land. Farmsteads along the St. Lawrence River were laid out in long strips, with one edge along the river and the farm building along a road; agriculture was on a subsistence level because the land was relatively infertile and the growing season short. New England farms were small subsistence farms, yielding rye, corn, barley, oats, and apples. Livestock was allowed to forage in woodlands. The larger farms of the middle colonies--New Jersey and Pennsylvania, for instance--originally grew New World crops because they were easier to plant and yielded more per hectare than Old World crops. These larger farms later introduced wheat, however, a crop that could be sold to the European market and that allowed farmers to become more commercial. Southern plantations--which used slave labor--covered hundreds of hectares and usually grew one crop intensively for commerce, particularly tobacco (introduced in 1614), rice (1696), indigo (mid-1700s), and cotton (1780s). Eli \TWhitney\t invented (1794) the cotton gin, which spurred Southern states to intensive cotton planting. 18th- and 19th-Century America After the American Revolution the U.S. federal government began to develop land policies that would promote settlement of the West quickly and at low cost. The Land Ordnance of 1785 stipulated that land be surveyed in square blocks; the Northwest Ordnance (see \TNorthwest Territory\t) encouraged free exchange of land. Federal expansion policies continued in the 1800s following the Louisiana Purchase (1803), the acquisition of Texas as a state (1845), the Oregon settlement (1846), and the Mexican Cession (1848). Such improved transportation as canals (see \TErie Canal\t), steamboats, and railroads allowed commercial crops to be shipped more easily and quickly to market. Wars in Europe increased the demand for cotton, tobacco, and food. Such inventions as Cyrus \TMcCormick\t's reaper (1831) and John \TDeere\t's steel plow (1837) allowed the heavy, rich soils of the prairie to be tilled, opening new regions for the cultivation of wheat. The invention of barbed wire and the steel windmill made farming possible in what had been open range for Texas longhorn cattle. Food-processing techniques, such as canning, improved flour milling, and refrigeration, were developed during the 1840s. Refrigeration was especially important in making it possible for such distant countries as Argentina (beef) and New Zealand (mutton, milk, butter, and cheese) to export food to Europe. In 1862, Abraham Lincoln signed the \THomestead Act\t, which allowed a settler 160 acres (64.7 ha) free after working it for 5 years. The U.S. Department of Agriculture was formed in 1862, which year also saw the passage into law of the \TMorrill Act\t, which granted land to states for the establishment of agricultural colleges (see \Tland-grant colleges\t). In 1867 the National \TGrange\t, an organization for the alleviation of poverty among farmers, was created. During the 1870s wheat farmers and cattle ranchers flourished in the prairies. A specific variety of wheat--Turkey Red--adapted particularly well to prairie soil, and wheat economy improved. Ranchers began to feed cattle grain, which resulted in better-quality beef sold to urban markets. The development of steam power resulted in mechanized \Lcombine\ls, \Ltractor\ls, and threshers, which further improved wheat farming. Although Canada's expansion policies did not open up prairie land until the 1870s, Thomas Douglas, 5th earl of \TSelkirk\t, attempted to establish an experimental colony in Manitoba in 1812. He had received a land grant from the Hudson's Bay Company for the site where present-day Winnipeg exists and brought Scotch and Irish settlers to work the land. Despite crop failure, the agricultural inexperience of the farmers, and hostilities of the neighboring metis (people of mixed French and Indian ancestry), this \TRed River Settlement\t eventually succeeded, especially after the introduction of an iron plow in 1824. Further colonization was minimal until legislation to section off land in squares and a homesteading act in 1870 encouraged immigration. In 1887 the \THatch Act\t, in the United States, ensured federal funding to land-grant colleges in order to set up agricultural experiment stations. During this time the agricultural scientist George Washington \TCarver\t developed soybean flour, 118 products from sweet potatoes, and 300 products from peanuts at his research station at Tuskegee Institute, Alabama, in an effort to spur economic growth in the South by developing new crop potentials. 20th-Century United States By the 1890s the gasoline tractor had been invented, providing power to do in minutes what took horses and farmers days. Gregor Johann \TMendel\t's theories of \Theredity\t came to light in the early 1900s, after which \Tplant breeding\t became a science. By 1910 most of the arable land in the United States had been settled, and with the foresight of the conservationist Gifford \TPinchot\t, methods for prevention of soil erosion began to be developed (see \Tconservation\t). In 1914 the \TSmith-Lever Act\t provided funding for extension work (see \Tagricultural extension service\t), which involves educators' traveling to instruct farmers and their families in farm management and home economics. U.S. and Canadian farmers mobilized to provide food for Europe during World War I. As a result of European postwar poverty and U.S. overproduction, however, farmers experienced a depression lasting from 1922 to 1927. Nevertheless, Clarence \TBirdseye\t perfected (1920s) a method for freezing foods, and supermarkets were springing up, both of which spurred farming of produce previously too perishable to be of commercial value. The Cooper-Volstead Act (1922) allowed farmers to join \Tcooperative\t organizations that controlled the marketing of their commodities, resulting in greater profits. Despite the progress, farmers' incomes were lower than the national level; therefore, legislative efforts to aid farmers began (see \Tagricultural economics\t; \Tparity\t). In the early 1930's \Ldrought\ls and dust storms caused by poor tillage practices devastated farms and ranches of the Great Plains (see \TDust Bowl\t). Franklin D. Roosevelt's \TNew Deal\t sought to satisfy the demands of striking farmers by a series of acts that included the Agricultural Adjustment Act (1933; see \TAgricultural Adjustment Administration\t)--by which the secretary of agriculture could control crop production and reduce unfair practices toward farmers--and acts to improve rural roads and introduce electricity and telephone service. The Agricultural Marketing Act (1937) improved prices for producers of perishables and allowed the federal government to buy surpluses, which were then donated to the poor and used in school-meal and food-stamp programs. During the 1930s more-powerful tractors were built, and harvesters for root and vegetable crops were invented. Hybrid corn was planted, and the Santa Gertrudis and American Brahman cattle, which could tolerate hot weather, were bred. By the 1960s farmers required a huge outlay of capital and demanding marketing skills to deal with suppliers and food distributors in a network known as \Tagribusiness\t. High-powered machinery, feed, fertilizers, and pesticides began to be used, and poultry was raised in completely controlled environments (see \Tfactory farming\t and \Tegg production\t). At the same time, lobbies of migrant laborers, environmental groups, and consumers began to affect agricultural policy. Some farmers initiated organic farming--using nonpolluting, nontoxic methods of cropping and animal breeding. The \Tgreen revolution\t of the 1960s, spearheaded by the plant geneticist Norman Ernest \TBorlaug\t, was the result of crop improvement programs established to help small farmers of developing nations. These programs continue, with emphasis now on breeding new crop varieties that need little fertilizer or irrigation. Once ignored plants such as soybeans, sunflowers, and sorghum have become major commercial crops, and research has encouraged the increasing cultivation of such arid-land plants as \Tjojoba\t and \Tguayule\t. Other exotic crops that are being grown as possible future commercial sources of food include \Tamaranth\t and quinao (cultivated for their nutritious seeds); triticale, a cross between wheat and rye that has a high yield and a rich protein content; and various tropical fruits, roots, and vegetables. In addition, \Tgenetic engineering\t offers the possibility of increasing crop yields by genetically implanting desired traits--disease resistance, for example--into agricultural plants, or by synthesizing hormones that can be used to increase growth rate or milk production in farm animals. The enormous increase in the production of basic foods has paradoxically created problems of oversupply in Europe and the United States, whose governments buy and stockpile vast amounts of such staples as wheat, cheese, and butter in order to maintain prices that will keep farming profitable. Reviewed by James H. Shideler Bibliography: Baker, Herbert G., Plants and Civilization, 3d ed. (1978); Bender, Barbara, Farming in Prehistory (1975); Carter, V. G., and Dale, T., Topsoil and Civilization, rev. ed. (1981); Cohen, M. N., The Food Crisis in Prehistory (1979); Duby, Georges, Rural Economy and Country Life in the Medieval West (1968); Frayn, J., Subsistence Farming in Roman Italy (1981); Grigg, D. B., The Dynamics of Agricultural Change (1983); Hutchinson, Joseph, et al., The Early History of Agriculture (1977); Killingray, Margaret, Agricultural Revolution (1980); King, Russell, Land Reform: A World Survey (1978); Rasmussen, Wayne, ed., Agriculture in the United States, 3 vols. (1979); Rasmussen, W., ed., Agriculture in the United States, 4 vols. (1979) Rhodes, R. E., Breaking New Ground: Agricultural Anthropology (1984); Rindos, D., The Origins of Agriculture: An Evolutionary Perspective (1984); Schafer, J., Social History of American Agriculture (1936; repr. 1970); Simmonds, N. W., ed., Evolution of Crop Plants (1979); Struever, Stuart, ed., Prehistoric Agriculture (1971).