I. INTRODUCTION

Agriculture, art, science, and industry of managing the growth of plants and animals for human use. In a broad sense agriculture includes cultivation of the soil, growing and harvesting crops, breeding and raising livestock, dairying, and forestry.Regional and national agriculture are covered in more detail in individual continent, country, state, and Canadian province articles.Modern agriculture depends heavily on engineering and technology and on the biological and physical sciences. irrigation, drainage, conservation, and sanitary engineering each of which is important in successful farming—are some of the fields requiring the specialized knowledge of agricultural engineers.Agricultural chemistry deals with other vital farming concerns, such as the application of fertilizers, insecticides, and fungicides, soil makeup, analysis of agricultural products, and nutritional needs of farm animals.Plant breeding and genetics contribute immeasurably to farm productivity. Genetics has also made a science of livestock breeding. Hydroponics, a method of soil less gardening in which plants are grown in chemical nutrient solutions, may help meet the need for greater food production as the world’s population increases.The packing, processing, and marketing of agricultural products are closely related activities also influenced by science. Methods of quick-freezing and dehydration have increased the markets for farm products. Mechanization, the outstanding characteristic of late 19th- and 20th-century agriculture, has eased much of the backbreaking toil of the farmer. More significantly, mechanization has enormously increased farm efficiency and productivity .Animals including horses, oxen, llamas, alpacas, and dogs, however, are still used to cultivate fields, harvest crops, and transport farm products to markets in many parts of the world.Airplanes and helicopters are employed in agriculture for seeding, spraying operations for insect and disease control, transporting perishable products, and fighting forest fires. Increasingly satellites are being used to monitor crop yields. Radio and television disseminate vital weather reports and other information such as market reports that concern farmers. Computers have become an essential tool for farm management.

II. WORLD AGRICULTURE

Over the 10,000 years since agriculture began to be developed, peoples everywhere have discovered the food value of wild plants and animals, and domesticated and bred them. The most important crops are cereals such as wheat, rice, barley, corn and rye; sugarcane and sugar beets; meat animals such as sheep, cattle, goats and pigs; poultry such as chickens, ducks, and turkeys; animal products such as milk, cheese and eggs; and nuts and oils. Fruits, vegetables, and olives are also major foods for people. Feed grains for animals include soybeans, field corn, and sorghum. Agricultural income is also derived from nonfood crops such as rubber, fiber plants, tobacco and oil seeds used in synthetic chemical compounds, as well as animals raised for pelts. Conditions that determine what is raised in an area include climate, water supply and waterworks terrain, and ecology. In 2003, 44 percent of the world’s labor force was employed in agriculture. The distribution ranged from 66 percent of the economically active population in sub-Saharan Africa to less than 3 percent in the United States and Canada. In Asia and the Pacific the figure was 60 percent; in Latin America and the Caribbean, 19 percent; and in Europe, 9 percent. Farm size varies widely from region to region. In the early 2000s the average for Canadian farms was about 273 hectares (about 675 acres) per farm; for farms in the United States, 180 hectares (440 acres). By contrast, the average size of a single land holding in India was 2 hectares (about 5 acres). Size also depends on the purpose of the farm. Commercial farming, or production for cash, usually takes place on large holdings. The latifundia of Latin America are large, privately owned estates worked by tenant labor. Single-crop plantations produce tea, rubber, and cocoa. Wheat farms are most efficient when they comprise thousands of hectares and can be worked by teams of people and machines. Australian sheep stations and other livestock farms must be large to provide grazing for thousands of animals. Individual subsistence farms or small-family mixed-farm operations are decreasing in number in developed countries but are still numerous in the developing countries of Africa and Asia. Nomadic herders range over large areas in sub-Saharan Africa, Afghanistan, and Lapland; and herding is a major part of agriculture in such areas as Mongolia. Much of the foreign exchange earned by a country may be derived from a single agricultural commodity; for example, Sri Lanka depends on tea, Denmark specializes in dairy products, Australia in wool, and New Zealand and Argentina in meat products. In the United States, wheat, corn, and soybeans have become major foreign exchange commodities in recent decades. The importance of an individual country as an exporter of agricultural products depends on many variables. Among them is the possibility that the country is too little developed industrially to produce manufactured goods in sufficient quantity or technical sophistication. Such agricultural exporters include Ghana, with cocoa, and Myanmar (formerly Burma), with rice. However, a developed country may produce surpluses that are not needed by its own population; this is the case with the United States, Canada, and some other countries. Because nations depend on agriculture not only for food but for national income and raw materials for industry as well, trade in agriculture is a constant international concern. It is regulated by the World Trade Organization. The Food and Agriculture Organization of the United Nations (FAO) directs much attention to agricultural trade and policies. According to the FAO, world agricultural production, stimulated by improving technology, grew steadily from the 1960s to the 1990s. Per capita food production saw sustained growth in Latin America, the Caribbean, Asia, and the Pacific, and limited growth in the Near East and North Africa. The only region not to experience growth during the 1980s and 1990s was sub-Saharan Africa, which suffered from climatic conditions that made agriculture difficult. Although agricultural growth began to taper off in the year 2000, it continued to outpace world population growth.

III. HISTORY

The history of agriculture may be divided into five broad periods of unequal length, differing widely in date according to region: prehistoric, historic through the Roman period, feudal, scientific, and industrial. A countertrend to industrial agriculture, known as sustainable agriculture or Organic Farming, may represent yet another period in agricultural history.

A. PREHISTORIC AGRICULTURE

Early farmers were, archaeologists agree, largely of Neolithic culture. Sites occupied by such people are located in southwestern Asia in what are now Iran, Iraq, Israel, Jordan, Syria and Turkey; in southeastern Asia, in what is now Thailand; in Africa, along the Nile River in Egypt; and in Europe, along the Danube River and in Macedonia, Thrace, and Thessaly (historic regions of southeastern Europe). Early centers of agriculture have also been identified in the Huang He (Yellow River) area of China; the Indus River valley of India and Pakistan; and the Tehuacán Valley of Mexico, northwest of the Isthmus of Tehuantepec. The dates of domesticated plants and animals vary with the regions, but most predate the 6th millennium bc, and the earliest may date from 10,000 bc. Scientists have carried out carbon-14 testing of animal and plant remains and have dated finds of domesticated sheep at 9000 bc in northern Iraq; cattle in the 6th millennium bc in northeastern Iran; goats at 8000 bc in central Iran; pigs at 8000 bc in Thailand and 7000 bc in Thessaly; onagers, or asses, at 7000 bc in Iraq; and horses around 4000 bc in central Asia. The llama and alpaca were domesticated in the Andean regions of South America by the middle of the 3rd millennium bc. According to carbon dating, wheat and barley were domesticated in the Middle East in the 8th millennium bc; millet and rice in China and Southeast Asia by 5500 bc; and squash in Mexico about 8000 bc. Legumes found in Thessaly and Macedonia are dated as early as 6000 bc. Flax was grown and apparently woven into textiles early in the Neolithic Period. The transition from hunting and food gathering to dependence on food production was gradual, and in a few isolated parts of the world this transition has not yet been accomplished. Crops and domestic meat supplies were augmented by fish and wildfowl as well as by the meat of wild animals. The farmer began, most probably, by noting which of the wild plants were edible or otherwise useful and learned to save the seed and to replant it in cleared land. Lengthy cultivation of the most prolific and hardiest plants yielded stable strains. Herds of goats and sheep were assembled from captured young wild animals, and those with the most useful traits—such as small horns and high milk production—were bred. The wild aurochs was the ancestor of European cattle, and an Asian wild ox of the zebu, was the ancestor of the humped cattle of Asia. Cats, dogs, and chickens were also domesticated very early. Neolithic farmers lived in simple dwellings—caves and small houses of sunbaked mud brick or reed and wood. These homes were grouped into small villages or existed as single farmsteads surrounded by fields, sheltering animals and humans in adjacent or joined buildings. In the Neolithic Period, the growth of cities such as Jericho (founded about 9000 bc) was stimulated by the production of surplus crops. Pastoralism (individual country living) may have been a later development. Evidence indicates that mixed farming, combining cultivation of crops and stock raising, was the most common Neolithic pattern. Nomadic herders, however, roamed the steppes of Europe and Asia, where the horse and camel were domesticated. The earliest tools of the farmer were made of wood and stone. They included the stone adz, an axlike tool with blades at right angles to the handle, used for woodworking; the sickle or reaping knife with sharpened stone blades, used to gather grain; the digging stick, used to plant seeds and, with later adaptations, as a spade or hoe; and a rudimentary plow, a modified tree branch used to scratch the surface of the soil and prepare it for planting. The plow was later adapted for pulling by oxen. The hilly areas of southwestern Asia and the forests of Europe had enough rain to sustain agriculture, but Egypt depended on the annual floods of the Nile River to replenish soil moisture and fertility. The inhabitants of the Fertile Crescent around the Tigris and Euphrates rivers in the Middle East also depended on annual floods to supply irrigation water. Drainage was necessary to prevent the erosion of land from the hillsides through which the rivers flowed. The farmers who lived in the area near the Huang He developed a system of irrigation and drainage to control the damage caused to their fields in the flood plain of the meandering river. Although Neolithic settlements were more permanent than the camps of hunting peoples, villages had to be moved periodically in some areas when the fields lost their fertility from continuous cropping. This was most necessary in northern Europe, where fields were produced by the slash-and-burn method of clearing. Settlements along the Nile River, however, were more permanent, because the river deposited fertile silt annually.

B. HISTORICAL AGRICULTURE THROUGH THE ROMAN EMPIRE

With the close of the Neolithic period and the introduction of metals, the age of innovation in agriculture was largely over. The historical period—known through written and pictured materials, including the Bible; Middle Eastern records and monuments; and Chinese, Greek, and Roman writings—was highlighted by agricultural improvements. A few high points must serve to outline the development of worldwide agriculture in this era, roughly defined as 2500 bc to ad 500. For a similar period of development in Central and South America, somewhat later in date. Some plants became newly prominent. Grapes and wine were mentioned in Egyptian records about 2900 bc, and trade in olive oil and wine was widespread in the Mediterranean area by the 1st millennium bc. Rye and oats were cultivated in northern Europe about 1000 bc. Many vegetables and fruits, including onions, melons, and cucumbers, were grown by the 3rd millennium bc in Ur (now Iraq). Dates and figs were an important source of sugar in the Middle East, and apples, pomegranates, peaches, and mulberries were grown in the Mediterranean area. Cotton was grown and spun in India about 2000 bc, and linen and silk were used extensively in 2nd-millennium bc China. Felt was made from the wool of sheep in Central Asia and the Russian steppes. The horse, introduced to Egypt about 1600 bc, was already domesticated in Mesopotamia and Asia Minor. The ox-drawn four-wheeled cart for farm work and two-wheeled chariots drawn by horses were familiar in northern India in the 2nd millennium bc. Improvements in tools and implements were particularly important. Tools of bronze and iron were longer lasting and more efficient, and cultivation was greatly improved by such aids as the ox-drawn plow fitted with an iron-tipped point, noted in the 10th century bc in Palestine. In Mesopotamia in the 3rd millennium bc a funnel-like device was attached to the plow to aid in seeding, and other early forms of seed drills were used in China. Farmers in China further improved efficiency with the invention of a cast-iron moldbar plow. Threshing was also done with animal power in Palestine and Mesopotamia, although reaping, binding, and winnowing were still done by hand. Egypt retained hand seeding through this period on individual farm plots and large estates alike. Storage methods for oil and grain were improved. Granaries—jars, dry cisterns, silos, and bins containing stored grain—provided food for city populations. Without adequate food supplies and trade in both food and nonfood items, the high civilizations of Mesopotamia, northern India, Egypt, Greece, and Rome would not have been possible. Irrigation systems in China, Egypt, and the Middle East were refined and expanded, putting more land into cultivation. The forced labor of peasants and the growth of bureaucracies to plan and supervise work on irrigation systems were probably basic in the development of the city-states of Sumer (now Iraq and Kuwait). Windmills and water mills, developed toward the end of the Roman period, increased control over the many uncertainties of weather. The introduction of fertilizer, mostly animal manures, and the rotation of fallow and crop land increased crop production. Mixed farming and stock raising, which were flourishing in the British Isles and on the continent of Europe as far north as Scandinavia at the beginning of the historical period, already displayed a pattern that persisted throughout the next 3,000 years. In many regions, fishing and hunting supplemented the food grown by farmers. About ad 100 Roman historian Cornelius Tacitus described the Germans as a tribal society of free peasant warriors who cultivated their own lands or left them to fight. About 500 years later, a characteristic European village had a cluster of houses in the middle, surrounded by rudely cultivated fields comprising individually owned farmlands; and meadows, woods, and wasteland were used by the entire community. Oxen and plow were passed from one field to another, and harvesting was a cooperative effort. The Roman Empire appears to have started as a rural agricultural society of independent farmers. In the 1st millennium bc, after the city of Rome was established, however, agriculture started a development that reached a peak in the Christian era. Large estates that supplied grain to the cities of the empire were owned by absentee landowners and cultivated by slave labor under the supervision of hired overseers. As slaves, usually war captives, decreased in number, tenants replaced them. The late Roman villa of the Christian era approached the medieval manor in organization; slaves and dependent tenants were forced to work on a fixed schedule, and tenants paid a predetermined share to the estate owner. By the 4th century ad, serfdom was well established, and the former tenant was attached to the land.

C. FEUDAL AGRICULTURE

The feudal period in Europe began soon after the fall of the Roman Empire, reaching its height about ad 1100. This period was also marked by development of the Byzantine Empire and the power of the Saracens in the Middle East and southern Europe. Agriculture in Spain, Italy, and southern France, in particular, was affected by events outside continental Europe. As the Arab influence extended to Egypt and later Spain, irrigation was extended to previously sterile or unproductive land. In Egypt, grain production was sufficient to allow the country to sell wheat in international markets. In Spain, vineyards were planted on sloping land, and irrigation water was brought from the mountains to the plains. In some areas of the Middle East, oranges, lemons, peaches, and apricots were cultivated. Rice, sugarcane, cotton, and vegetables such as spinach and artichokes, as well as the characteristic Spanish flavoring saffron, were produced. The silkworm was raised and its food, the mulberry tree, was grown. By the 12th century agriculture in the Middle East had become static, and Mesopotamia declined to subsistence production levels when irrigation systems were destroyed by invading Mongols. The Crusades, however, increased European contact with Islamic lands and familiarized western Europe with citrus fruits and silk and cotton textiles.The structure of agriculture was not uniform. In Scandinavia and eastern Germany, the small farms and villages of previous years remained. In mountainous areas and in the marshlands of Slavic Europe, the manorial system could not flourish. A manor required roughly 350 to 800 hectares (about 900 to 2,000 acres) of arable land and the same amount of other prescribed lands, such as wetlands, wood lots, and pasture. Typically, the manor was a self-contained community. On it was the large home of the holder of the fief—a military or church vassal of rank, sometimes given the title lord—or of his steward. A parish church was frequently included, and the manor might make up the entire parish. One or more villages might be located on the manor, and village peasants were the actual farmers. Under the direction of an overseer, they produced the crops, raised the meat and draft animals, and paid taxes in services, either forced labor on the lord’s lands and other properties or in forced military service. A large manor had a mill for grinding grain, an oven for baking bread, fishponds, orchards, perhaps a winepress or oil press, and herb and vegetable gardens. Bees were kept to produce honey. Woolen garments were produced from sheep raised on the manor. The wool was spun into yarn, woven into cloth, and then sewn into clothing. Linen textiles could also be produced from flax, which was grown for its oil and fiber. The food served in a feudal castle or manor house varied according to the season and the lord’s hunting prowess. Hunting for meat was, indeed, the major nonmilitary work of the lord and his military retainers. The castle residents could also eat domestic ducks, pheasants, pigeons, geese, hens, and partridges; fish, pork, beef, and mutton; and cabbages, turnips, carrots, onions, beans, and peas. Bread, cheese and butter, ale and wine, and apples and pears also appeared on the table. In southern Europe olives and olive oil might be used, often instead of butter. Leather was produced from the manor’s cattle. Horses and oxen were the beasts of burden; as heavier horses were bred and a new kind of harness was developed, they became more important. A blacksmith, wheelwright, and carpenter made and maintained crude agricultural tools. The cultivation regime was rigidly prescribed. The arable land was divided into three fields: one sown in the autumn in wheat or rye; a second sown in the spring in barley, rye, oats, beans, or peas; and the third left fallow. The fields were laid out in strips distributed over the three fields, and without hedges or fences to separate one strip from another. Each male peasant head of household was allotted about 30 strips. Helped by his family and a yoke of oxen, he worked under the direction of the lord’s officials. When he worked on his own fields, if he had any, he followed village custom that was probably as rigid as the rule of an overseer. About the 8th century a four-year cycle of rotation of fallow appeared. The annual plowing routine on 400 hectares would be 100 hectares plowed in the autumn and 100 in the spring, and 200 hectares of fallow plowed in June. These three periods of plowing, over the year, could produce two crops on 200 hectares, depending on the weather. Typically, ten or more oxen were hitched to the tongue of the plow, often little more than a forked tree trunk. The oxen were no larger than modern heifers. At harvest time, all the peasants, including women and children, were expected to work in the fields. After the harvest, the community’s animals were let loose on the fields to forage. Some manors used a strip system. Each strip, with an area of roughly 0.4 hectare (about 1 acre), measured about 200 m (about 220 yd) in length and from 1.2 to 5 m (4 to 16.5 ft) in width. The lord’s strips were similar to those of the peasants distributed throughout good and bad field areas. The parish priest might have lands separate from the community fields or strips that he worked himself or that were worked by the peasants. In all systems, the lord’s fields and needs came first, but about three days a week might be left for work on the family strips and garden plots. Wood and peat for fuel were gathered from the commonly held wood lots, and animals were pastured on village meadows. When surpluses of grain, hides, and wool were produced, they were sent to market. In about 1300 a tendency developed to enclose the common lands and to raise sheep for their wool alone. The rise of the textile industry made sheep raising more profitable in England, Flanders (now in Belgium), Champagne (France), Tuscany and Lombardy (Italy), and the Augsburg region of Germany. At the same time, regions about the medieval towns began to specialize in garden produce and dairy products. Independent manorialism was also affected by the wars of 14th- and 15th-century Europe and by the widespread plague outbreaks of the 14th century. Villages were wiped out, and much arable land was abandoned. The remaining peasants were discontented and attempted to improve their conditions. With the decline in the labor force, only the best land was kept in cultivation. In southern Italy, for instance, irrigation helped increase production on the more fertile soils. The emphasis on grain was replaced by diversification, and items requiring more care were produced, such as wine, oil, cheese, butter, and vegetables.

D. SCIENTIFIC AGRICULTURE

By the 16th century, population was increasing in Europe, and agricultural production was again expanding. The nature of agriculture there and in other regions was to change considerably in succeeding centuries. Several reasons can be identified for this trend. Europe was cut off from Asia and the Middle East by an extension of Ottoman power. New economic theories were put into practice, directly affecting agriculture. Continued wars between England and France, within each of these countries, and in Germany consumed capital and human resources. A new period of global exploration and colonization was undertaken to circumvent the Ottoman Empire’s control of the spice trade, to provide homes for religious refugees, and to provide new resources for European nations convinced that only precious metals constituted wealth. Colonial agriculture was intended not only to feed the colonists but also to produce cash crops and to supply food for the home country. This meant cultivation of such crops as sugar, cotton, tobacco, and tea, and production of animal products such as wool and hides. From the 15th to the 19th century the slave trade provided laborers needed to fill the large workforce required by colonial plantations. Many early slaves replaced indigenous peoples who died from diseases carried by the colonists or were killed by hard agricultural labor to which they were unaccustomed. Slaves from Africa worked, for example, on sugar plantations in the Caribbean region and on indigo and cotton plantations in what would become the southern United States. Native Americans were virtually enslaved in Mexico. Indentured slaves from Europe, especially from the prisons of Great Britain, provided both skilled and unskilled labor to many colonies. Both slavery and serfdom were substantially wiped out in the 19th century. When encountered by the Spanish conquistadors, the more advanced Native Americans in the New World—the Aztec, Inca and Maya—already had intensive agricultural economies, but no draft or riding animals and no wheeled vehicles. Squash, beans, peas, and corn had long since been domesticated. Land was owned by clans and other kinship groups or by ruling tribes that had formed sophisticated governments, but not by individuals or individual families. Several civilizations had risen and fallen in Central and South America by the 16th century. The scientific revolution resulting from the Renaissance and the Age of Enlightenment in Europe encouraged experimentation in agriculture as well as in other fields. Trial-and-error efforts in plant breeding produced improved crops, and a few new strains of cattle and sheep were developed. Notable was the Guernsey cattle breed, which is still a heavy milk producer. Land enclosure was increasingly practiced in the 18th century, enabling individual landowners to determine the disposition of cultivated land and pasture that previously had been subject to common use. Crop rotation, involving alternation of legumes with grain, was more readily practiced outside the village strip system inherited from the manorial period. In England, where scientific farming was most efficient, enclosure brought about a fundamental reorganization of land ownership. From 1660 large landowners had begun to add to their properties, frequently at the expense of small independent farmers. By the mid-19th century the agricultural pattern was based on the relationship between the landowner, dependent on rents; the farmer, producer of crops; and the landless laborer, the hired hand of American farming lore. Drainage brought more land into cultivation, and, with the Industrial Revolution, farm machinery was introduced. It is not possible to fix a clear decade or series of events as the start of the agricultural revolution through technology. Among the important advances were the purposeful selective breeding of livestock, begun in the early 1700s, and the spreading of limestone on farm soils in the late 1700s. Mechanical improvements in the traditional wooden plow began in the mid-1600s with small iron points fastened onto the wood with strips of leather. In 1797, Charles Newbold, a blacksmith in Burlington, New Jersey, reconceived of the cast-iron moldboard plow (first used in China nearly 2,000 years earlier). John Deere, another American blacksmith, further improved the plow in the 1830s and manufactured it in steel. Other notable inventions included the seed drill of English farmer Jethro Tull, developed in the early 1700s and progressively improved for more than a century; the reaper of American Cyrus McCormick in 1831; and numerous new horse-drawn threshers, cultivators, grain and grass cutters, rakes, and corn shellers. By the late 1800s, steam power was frequently used to replace animal power in drawing plows and in operating threshing machinery. The demand for food for urban workers and raw materials for industrial plants produced a realignment of world trade. Science and technology developed for industrial purposes were adapted for agriculture, eventually resulting in the agribusinesses of the mid-20th century. In the 17th and 18th centuries the first systematic attempts were made to study and control pests. Before this time, handpicking and spraying were the usual methods of pest control. In the 19th century, poisons of various types were developed for use in sprays, and biological controls such as predatory insects were also used. Resistant plant varieties were cultivated; this was particularly successful with the European grapevine, in which the grape-bearing stems were grafted onto resistant American rootstocks to defeat the Phylloxera aphid. Improvements in transportation affected agriculture. Roads, canals, and rail lines enabled farmers to obtain needed supplies from remote suppliers and market their produce over a wider area. Food could be protected during transport more economically than before as the result of rail, ship, and refrigeration developments in the late 19th and early 20th centuries. Efficient use of these developments led to increasing specialization and eventual changes in the location of agricultural suppliers. In the last quarter of the 19th century, for example, Australian and North American suppliers displaced European suppliers of grain in the European market. When grain production proved unprofitable for European farmers, or an area became more urbanized, specialization in dairying, cheesemaking, and other products was emphasized. The impetus toward increased food production following World War II (1939-1945) was a result of a new population explosion. A so-called green revolution, involving selective breeding of traditional crops for high yields, new hybrids, and intensive cultivation methods adapted to the climates and cultural conditions of densely populated countries such as India, temporarily stemmed the pressure for more food. A worldwide shortage of petroleum in the mid-1970s, however, reduced the supplies of nitrogen fertilizer essential for the success of the new varieties. Simultaneously, erratic weather and natural disasters such as drought and floods reduced crop levels throughout the world. Famine became common in many parts of Africa south of the Sahara. Economic conditions, particularly uncontrolled inflation, threatened the food supplier and the consumer alike. These problems became the determinants of agricultural change and development.

E. INDUSTRIAL AGRICULTURE

Many of the innovations introduced to agriculture by the scientific and Industrial revolutions paved the way for a qualitative change in the nature of agricultural production, particularly in advanced capitalist countries. This qualitative change became known as industrial agriculture. It is characterized by heavy use of synthetic fertilizers and pesticides; extensive irrigation; large-scale animal husbandry involving animal confinement and the use of hormones and antibiotics; reliance on heavy machinery; the growth of agribusiness and the commensurate decline of family farming; and the transport of food over vast distances. Industrial agricultural has been credited with lowering the cost of food production and hence food prices, while creating profitable businesses and many jobs in the agricultural chemistry and biotechnology industries. It has also allowed farmers and agribusinesses to export a large percentage of their crops to other countries. Farm exports have enabled farmers to expand their markets and have contributed to aiding a country’s trade balance. At the same time, industrial-scale agriculture has had adverse environmental consequences, such as intensive use of water, energy, and chemicals. Many aquifers and other water reservoirs are being drained faster than they can be renewed. The energy required to produce nitrogen-based synthetic fertilizers, to operate heavy farm equipment, to manufacture pesticides, and to transport food over long distances involves burning large amounts of fossil fuels, which in turn contribute to air pollution and global warming. The use of synthetic fertilizers has affected the ability of soil to retain moisture, thus increasing the use of irrigation systems. Fertilizer runoff has also stimulated algae growth in water systems. Finally, herbicides and insecticides in many cases have contaminated ground and surface waters. During the 20th century, a reaction developed to industrial agriculture known as sustainable agriculture. While industrial agriculture aims to produce as much food as possible at the lowest cost, the main goal of sustainable agriculture is to produce economically viable, nutritious food without damaging natural resources such as farmland and the local watershed. Examples of sustainable agricultural practices include rotating crops from field to field to prevent the depletion of nutrients from the soil, using fertilizers produced naturally on the farm rather than synthetic products, and planting crops that will grow without needing extensive irrigation. Sustainable agricultural practices have seen great success in parts of the developing world where resources such as arable land and water are in short supply and must be carefully utilized and conserved.

IV. AGRICULTURE IN THE UNITED STATES

In North America, agriculture had progressed significantly before European colonists arrived. There is evidence that corn, or maize, was cultivated at least as early as 3,000 years ago in the southwestern United States. Although few Native Americans relied on domesticated animals, some groups had advanced methods of cultivating food crops. The Wampanoag peoples of what is now Massachusetts, for example, fertilized their corn seeds by burying fish in the ground near the seeds. The Iroquois of the eastern United States exploited the natural relationship between plants to make their crops more productive. They planted corn, beans, and squash together in small groups, so that the corn plants supported the beans, the nitrogen released by the roots of the bean plants fertilized the corn, and the sprawling squash vines reduced the number of weeds. Corn, beans, squash, potatoes, tomatoes, peanuts, cacao (chocolate), and many other plants were originally domesticated by Native Americans. Until the 19th century, agriculture in the United States shared the history of European and colonial areas and was dependent on European sources for seed, stocks, livestock, and machinery, such as it was. That dependency, especially the difficulty in procuring suitable implements, made American farmers somewhat more innovative. They were aided by the establishment of societies that lobbied for governmental agencies of agriculture; the voluntary cooperation of farmers through associations; and the increasing use of various types of power machinery on the farm. Government policies traditionally encouraged the growth of land settlement. The Homestead Act of 1862 and the resettlement plans of the 1930s were the key agricultural legislative acts of the 19th and 20th centuries. In the 20th century steam, gasoline, diesel, and electric power came into wide use. Chemical fertilizers were manufactured in greatly increased quantities, and soil analysis was widely employed to determine the elements needed by a particular soil to maintain or restore its fertility. The loss of soil by erosion was extensively combated by the use of cover crops (quick-growing plants with dense root systems to bind soil); contour plowing in which the furrows follow the contour of the land and are level, rather than running up and down hills and providing channels for runoff water; and strip cropping (sowing strips of dense-rooted plants to serve as water-breaks or windbreaks in fields of plants with loose root systems. Selective breeding produced improved strains of both farm animals and crop plants. Hybrids (offspring of unrelated varieties or species) of desirable characteristics were developed; especially important for food production was the hybridization of corn in the 1930s. New uses for farm products, by-products, and agricultural wastes were discovered. Standards of quality, size, and packing were established for various fruits and vegetables to aid in wholesale marketing. Among the first to be standardized were apples, citrus fruits, celery, berries, and tomatoes. Improvements in storage, processing, and transportation also increased the widespread marketability of farm products. The use of cold storage warehouses and refrigerated railroad cars was supplemented by the introduction of refrigerated motor trucks, rapid delivery by airplane, and the quick-freeze process of preservation in which farm produce is frozen and packaged the same day that it is picked. Freeze-drying and irradiation have also reached practical application for many perishable foods. Scientific methods are now applied to pest control, limiting overuse of insecticides and fungicides and employing more varied and targeted application techniques. New understanding of significant biological control measures and the emphasis on integrated pest management make possible more effective control of certain kinds of insects. Chemicals for weed control are important for a number of crops, such as cotton and corn. The increasing use of chemicals for the control of insects, diseases, and weeds, however, has resulted in additional environmental problems and regulations that place strong demands on the skill of farmers.Since the 1970s high technology farming, including new hybrids for wheat, rice, and other grains, better methods of soil conservation and irrigation, and the growing use of improved fertilizers has led to the production of more food per capita, not only in the United States, but in much of the rest of the world. United States farmers, however, still have the advantage of superior private and government research facilities to produce and perfect new technologies. New applications of technologies at the beginning of the 21st century are further improving crop production. Precision farming, also known as prescription farming, site-specific farming, or variable rate farming, utilizes global positioning system (GPS) and geographic information systems (GIS) in the satellite collection and transmission of data to create yield maps of fields during harvest. Farmers use the yield maps as they plant and fertilize their crops the following season. This increases crop production while reducing the use of both fertilizers and fuel. GPS also helps farmers comply with environmental regulations when applying fertilizers and pesticides. Biotechnology is also increasing agricultural productivity. In recent years farmers have begun producing a new, genetically engineered oil seed crop that grows from canola, an oil seed producing plant, to yield lauric oil, which comes naturally from coconuts and palm kernels. New hybrid corn seed recently developed to resist the corn borer, an insect poisonous to that crop, and improved varieties of barley with disease resistant genes are now under cultivation, as well. Biotechnology developments have also become increasingly controversial, however, because it is difficult to determine the environmental consequences of genetically engineered organisms. Some people, including some scientists, object to any procedure that changes the genetic composition of an organism. Critics are concerned that some of the genetically altered forms will eliminate existing species, thereby upsetting the natural balance of organisms.

A. GOVERNMENT PRICE SUPPORT POLICIES

One of the recurring problems of American agriculture in the 20th century has been the tendency of farm income to lag behind increases in the costs of production. The problem began in the 1920s, following a period of exceptional prosperity for U.S. farmers. After the outbreak of World War I (1914-1918) the United States became the chief source of food for the warring nations of Europe, with American farmers investing heavily in new land and equipment, and bringing some 16 million additional hectares (about 40 million acres) of land under cultivation. These measures raised production levels until 1920, when the European demand for U.S. farm products suddenly declined, and prices began a continuing downward spiral. Agricultural income between 1910 and 1914 later became a standard for the level of farm prices in relation to general price levels. This established the basis for a concept called parity, a level for farm-product prices maintained by support from the federal government to keep farming as an essential part of the U.S. economy. Although attempts were under way to ease the economic difficulties of the farmer, farm income had not begun to recover when the Great Depression of the 1930s intensified these problems even more. By 1932 the level of farm prices was only about 65 percent of the average for the period from 1910 to 1914. Farmers continued to produce almost as much as before, and even increased their production in an attempt to maintain their income. This only lowered farm prices further. By comparison, manufacturers could control their production, thereby maintaining price levels to a certain degree. Although prices for industrial goods declined, they did not drop as severely as farm prices. As a result, by 1932 farmers were receiving only 58 cents from the sale of their products for every dollar they had to pay for nonfarm items. The federal government, which had done little in the 1920s to help farmers, initiated remedial programs during the administration of President Franklin D. Roosevelt. One approach was to reduce the supply of basic farm commodities. The Agricultural Adjustment Act of 1933 provided payments to farmers in return for agreements to curtail their acreage or their production of wheat, cotton, rice, tobacco, corn, hogs, and dairy products. The act was declared unconstitutional in 1936, but in 1938, after several changes in the membership of the United States Supreme Court, Congress passed a second Agricultural Adjustment Act under which production quotas were set as before. Payments were financed from taxes imposed on processors and were based on parity. The government also loaned money to farmers to enable them to withhold crops from the market when prices were low and to store the produce so that it might be available in poor crop years. A third method to limit production provided payments for shifting acreage of soil-depleting crops such as corn, wheat, cotton, tobacco, and rice to soil-conserving plants such as grasses and legumes and for implementing soil restoration practices. In 1939 an all-risk crop insurance program was initiated for interested farmers to prevent economic distress in case of crop failure for hail, floods, and other natural disasters. Until World War II the problem of low farm prices was not basically a result of overproduction. Rather, it was a consequence of the cycles of business and weather, and of problems of transportation, and credit. Following World War II, however, overproduction became a serious problem. Both during and immediately after the war, farm prices were generally high. Because production costs were also high, parity payments remained in force. Federal transactions in surplus commodities, primarily the sale of some commodities at prices less than those paid to farmers, proved costly for the government. To reduce costs of the federal farm program, the administration of President Dwight D. Eisenhower proposed that flexible, or variable, price supports replace the rigid 90 percent of parity that was in force. A bill authorizing a sliding scale of payments at 82.5 percent to 90 percent of parity on the basic commodities was enacted by the congress in 1954. The Agricultural Act of 1956, otherwise known as the soil-bank program, authorized federal payments to farmers if they reduced production of certain crops. A subsidy plan was formulated to pay farmers for converting part of their cropland to soil-conserving uses. In practice, farmers shared the costs of planting trees or grasses and received annual payments compensating them for the economic loss incurred by the removal of some of their land from crop production. The Department of Agriculture in the administrations of Presidents John Kennedy and Lyndon Johnson during the 1960s made control of overproduction a primary goal of farm policy. Farmers were offered payments in what amounted to a rental for part of their land, which would be taken out of production the following year. At the same time, measures were implemented to expand export markets for agricultural products. During this period the ratio of a farmer’s per capita income to that of a non-farm person increased from about 50 percent to about 75 percent. Direct subsidies for withholding agricultural land from production were phased out in 1973, as a result of a proposal by President Richard M. Nixon. Net farm income swelled to $33.3 billion that year. Poor grain harvests throughout the world, particularly in the Soviet Union, prompted massive sales of U.S. government-owned grain reserves in the 1970s. Global climatic conditions also helped keep worldwide demand for U.S. produce high through the mid-1970s. Soon however, exports lessened, prices dropped, and farm income began to fall, again without a corresponding decrease in costs of production. U.S. net farm income in 1976 fell to $18.7 billion. In 1978, a limited, voluntary output restriction was begun by President Jimmy Carter. Called the Farmer-Held Grain Reserve Program, the action took grains off the market for up to three years or until market prices reached predetermined levels. The program was also intended to provide adequate reserves of essential commodities such as corn and wheat, lessen food-price gyrations and combat inflation, give livestock producers protection from extremes in feed costs, and contribute to greater continuity in foreign food aid. On January 4, 1980, President Carter declared a limited suspension of grain sales to the USSR in response to that country’s invasion of Afghanistan. Additional restrictions included a prohibition on sales of U.S. phosphate. Despite the grain embargo, the United States continued to honor a five-year agreement already in effect that committed it to sell 8 million tons of grain to the Soviet Union annually. Despite efforts by President Carter’s opposition to void the embargo in 1980, an election year, it remained in effect. Administration officials argued that the Soviets had never been a major customer or even a reliable buyer. American farmers maintained, however, that the action was taken at their expense and made 1980 one of their worst years. In fact, U.S. farm exports in 1980 reached an all-time high of $40 billion, but the continued rise in costs of production and an extremely hot summer with accompanying droughts affected many farmers adversely. A new crop insurance program, passed by Congress in the fall of 1980, offered relief from such conditions rather than forcing farmers to rely on disaster loans, which amounted to $30 million for feed alone that year. When President Ronald Reagan took office in 1981, he lifted the embargo and extended the agreement that allowed the USSR to purchase 8 million tons of grain yearly from the United States. The two nations then signed a new five-year agreement in 1983 that obligated the USSR to import a minimum of 9 million tons of U.S. grain every year. Since the breakup of the former Soviet Union, the United States has continued to sell large amounts of wheat to Russia as well as to China. In 1996 the U.S. Congress passed the Federal Agricultural Improvement and Reform Act (FAIR), which was signed into law by President Bill Clinton. The act was the most far-reaching federal farm program in 60 years. FAIR replaced existing farm price-support programs with a system of transition payments designed to let both domestic and export markets, rather than the government, determine crop production. It also increased the flexibility of farmers to plant crops to meet world market demands. In addition, FAIR included food and nutrition, rural economic development, and agricultural market-promotion programs, phased out dairy subsidies, and provided environmental incentives to encourage farmers to preserve wetlands and conserve non-crop-producing acreage.

B. FARMING REGIONS

The United States has ten major farming areas. They vary by soil, terrain, climate, and distance to markets and storage and marketing facilities. The states of the Northeast and the Great Lake states are the country’s principal milk-producing areas. Climate and soil there are suited to raising grains and forage for cattle and for pastures. Chicken production is important to Maine, Delaware, and Maryland. Fruits and vegetables are also important to the region. The Appalachian region is the major tobacco-producing area of the nation. Peanuts, cattle, and dairy production also are important. Beef cattle and chickens are the major livestock products in the southeastern states; fruits and vegetables and peanuts are also grown. Florida has vast citrus groves and winter vegetable production areas. In the Mississippi Delta states, principal cash crops are soybeans and cotton. Rice and sugarcane are grown in the more humid and wet areas. With improved pastures, livestock production has gained importance in recent years. It also is a major chicken-producing region. The Corn Belt, extending from Ohio through Iowa, has rich soil, good climate, and sufficient rainfall for excellent farming. Corn, beef cattle, hogs, and dairy products are of primary importance. Other feed grains, soybeans, and wheat also are grown. The northern and southern states of the Great Plains, extending from Canada to Mexico and from the Corn Belt to the Rocky Mountains, are restricted by low rainfall in the western portion and by cold winters and short growing seasons in the north. But about 60 percent of the nation’s winter and spring wheat is grown in this region. Other small grains, grain sorghums, hay, forage crops, and pastures help make cattle important in these states. Cotton is produced in the southern area. The Rocky Mountain states provide yet a different terrain. Vast areas are suited to cattle and sheep. Wheat is important in the north. Irrigation in the valleys provides water for hay, sugar beets, potatoes, fruits, and vegetables. The Pacific region includes California, Oregon, and Washington, plus Alaska and Hawaii. In the northern mainland, farmers raise wheat, apples and other fruit, and potatoes. Dairy farming, vegetables, and barley are important to Alaska. Many farmers in the southern part of the region have large tracts on which they raise vegetables, fruit, and cotton, usually with irrigation. Cattle are raised throughout the region. Hawaii grows sugarcane and pineapple as its major crops.

C. AGRICULTURE RESOURCES

The total land area of the United States is 916.2 million hectares (2,264 million acres), of which 42 percent is used to produce crops and livestock. The rest is distributed among forest land (33 percent) and urban, transportation, and other uses. At the beginning of the 21st century, cropland resources comprised 174 million hectares (431 million acres). About 82 percent of cropland is cultivated, including 32 million hectares (79 million acres) used for corn, 26 million hectares (64 million acres) used for hay, and 25 million hectares (61 million acres) used for wheat. More than 50 percent of croplands are prime farmland, the best land for producing food and fiber. The nation has another nearly 400 million hectares (almost 1 billion acres) of nonfederal rural land currently being used for pastures, range, forest, and other purposes. About 27.5 million hectares (about 68 million acres) of this land are suitable for conversion to cropland if needed.

D. RECENT CHANGES

The history of agriculture in the United States since the Great Depression has been one of consolidation and increasing efficiency. From a high of 6.8 million farms in 1935, the total number declined to 2.1 million by 2005. In 2005 the area devoted to farms occupied 378 million hectares (933 million acres). Average farm size in 1935 was about 63 hectares (about 155 acres); in 2005 it was 180 hectares (444 acres). About 3.9 million people lived on farms according to the 2000 U.S. census, based on a farm definition introduced in 1977 to distinguish between rural residents and people who earned $1,000 or more from annual agricultural product sales. The farm population continues to constitute a declining share of the nation’s total; about 1 person in every 72, or 1.4 percent of the nation’s 281 million people in 2000, were farm residents. Total value of land and buildings on U.S. farms in 2002 was $1.19 trillion. The value of products sold was about $200 billion. Overall net farm income reached a record high of $85.5 billion in 2004, of which government subsidies accounted for 14.6 percent. Not including real estate, major expenditures by farmers in 2002 were for feed ($31.7 billion); purchases of livestock and poultry ($27.4 billion); fertilizer, chemicals, and seeds ($25 billion); hired labor ($22 billion); and fuel ($6.7 billion). Outstanding farm debt in 2002 was $193.3 billion, of which 53 percent was owed on real estate. Interest payments on the mortgage debt were about $8.6 billion per year. In 1980 a report based on projections by the U.S. government stated that in the next 20 years world food requirements would increase tremendously, with developed countries requiring most of the increase, and that food prices would double. Less than five years later, however, the U.S. farmer was enveloped in a major crisis caused by exceptionally heavy farm debts, mounting farm subsidy costs, and rising surpluses. A number of farmers were forced into foreclosure. The ailing Farm Credit System, a group of 37 farmer-owned banks under the Farm Credit Administration appealed to the government for a $5 to $6 billion fund that would keep the system solvent despite the weak national farm economy. After initial resistance, President Reagan signed legislation in December 1985 designed to create the Farm Credit System Capital Corporation to take over bad loans from the system’s banks and to assume responsibility for foreclosing or restructuring distressed loans. President Reagan also signed the Food Security Act of 1985, legislation designed to govern the nation’s farm policies for the next five years, trim farm subsidies, and stimulate farm exports. In the early 1990s, although farms generally still struggled to be economically viable, fewer farms faced the kinds of crises prevalent in the 1980s. Government assistance to farms steadily decreased; for example, the number of acres placed in federal commodity programs, which pay farmers to leave acres uncultivated, decreased by nearly 84 percent from 1987 to 1992. Farm subsidies began to increase again between 1995 and 2003 in response to low commodity prices and natural disasters, with such legislation as the Freedom to Farm Act (1996) and the Farm Security and Rural Investment Act (2002). In all, Congress passed emergency farm assistance legislation five times between 1998 and 2001. Following these measures, the national farming debt-to-equity ratio decreased each year from 2002 to 2005.

E. AGRICULTURAL EXPORTS

The United States is the world’s principal exporter of agricultural products, followed by Netherlands, France, Germany, Brazil, Belgium, and Italy. In 2004 the value of U.S. agricultural products exported was $64 billion. A substantial percentage of the wheat, soybeans, rice, cotton, tobacco, and corn for grain produced in the United States is exported. The major foreign markets are Asia, Western Europe, and Latin America. Japan heads the list of individual countries that import U.S. farm products.