Maize in the context of Sierra Mixe corn

An agricultural subsidy (also called an agricultural incentive) is a government incentive paid to agribusinesses, agricultural organizations and farms to supplement their income, manage the supply of agricultural products, and influence the cost and supply of such commodities.

Examples of such commodities include: wheat, feed grains (grain used as fodder, such as maize or corn, sorghum, barley and oats), cotton, milk, rice, peanuts, sugar, tobacco, oilseeds such as soybeans and meat products such as beef, pork, and lamb and mutton.

Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575–585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the RGB color model, used to create colors on television and computer screens, yellow is a secondary color made by combining red and green at equal intensity. Carotenoids give the characteristic yellow color to autumn leaves, corn, canaries, daffodils, and lemons, as well as egg yolks, buttercups, and bananas. They absorb light energy and protect plants from photo damage in some cases. Sunlight has a slight yellowish hue when the Sun is near the horizon, due to atmospheric scattering of shorter wavelengths (green, blue, and violet).

Because it was widely available, yellow ochre pigment was one of the first colors used in art; the Lascaux cave in France has a painting of a yellow horse 17,000 years old. Ochre and orpiment pigments were used to represent gold and skin color in Egyptian tombs, then in the murals in Roman villas. In the early Christian church, yellow was the color associated with the Pope and the golden keys of the Kingdom, but it was also associated with Judas Iscariot and used to mark heretics. In the 20th century, Jews in Nazi-occupied Europe were forced to wear a yellow star. In China, bright yellow was the color of the Middle Kingdom, and could be worn only by the emperor and his household; special guests were welcomed on a yellow carpet.

A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize (corn). Edible grains from other plant families, such as amaranth, buckwheat and quinoa, are pseudocereals. Most cereals are annuals, producing one crop from each planting, though rice is sometimes grown as a perennial. Winter varieties are hardy enough to be planted in the autumn, becoming dormant in the winter, and harvested in spring or early summer; spring varieties are planted in spring and harvested in late summer. The term cereal is derived from the name of the Roman goddess of grain crops and fertility, Ceres.

Cereals were domesticated in the Neolithic around 8,000 years ago. Wheat and barley were domesticated in the Fertile Crescent. Rice and some millets were domesticated in East Asia, while sorghum and other millets were domesticated in West Africa. Maize was domesticated by Indigenous peoples of the Americas in southern Mexico about 9,000 years ago. In the 20th century, cereal productivity was greatly increased by the Green Revolution. This increase in production has accompanied a growing international trade, with some countries producing large portions of the cereal supply for other countries.

Rice is a cereal grain and in its domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species Oryza sativa (Asian rice)—or, much less commonly, Oryza glaberrima (African rice). Asian rice was domesticated in China some 13,500 to 8,200 years ago; African rice was domesticated in Africa about 3,000 years ago. Rice has become commonplace in many cultures worldwide; in 2023, 800 million tons were produced, placing it third after sugarcane and maize. Only some 8% of rice is traded internationally. China, India, and Indonesia are the largest consumers of rice. A substantial amount of the rice produced in developing nations is lost after harvest through factors such as poor transport and storage. Rice yields can be reduced by pests including insects, rodents, and birds, as well as by weeds, and by diseases such as rice blast. Traditional rice polycultures such as rice-duck farming, and modern integrated pest management seek to control damage from pests in a sustainable way.

Dry rice grain is milled to remove the outer layers; depending on how much is removed, products range from brown rice to rice with germ and white rice. Some is parboiled to make it easy to cook. Rice contains no gluten; it provides protein but not all the essential amino acids needed for good health. Rice of different types is eaten around the world. The composition of starch components within the grain, amylose and amylopectin, gives it different texture properties. Long-grain rice, from the Indica cultivar, tends to stay intact on cooking, and is dry and fluffy. The aromatic rice varieties, such as basmati and jasmine, are widely used in Asian cooking, and distinguished by their bold and nutty flavor profile. Medium-grain rice, from either the Japonica or Indica cultivar, or a hybrid of both, is moist and tender and tends to stick together. Its varieties include Calrose, which founded the Californian rice industry, Carnaroli, attributed as the king of Italian rice due to its excellent cooking properties, and black rice, which looks dark purple due to high levels of anthocyanins, and is also known as forbidden rice as it was reserved for the consumption of the royal family in ancient China. Short-grain rice, primarily from the Japonica cultivar, has an oval appearance and sticky texture. It is featured heavily in Japanese cooking such as sushi (with rice such as Koshihikari, Hatsushimo, and Sasanishiki, unique to different regions of climate and geography in Japan), as it keeps its shape when cooked. It is also used for sweet dishes such as mochi (with glutinous rice), and in European cuisine such as risotto (with arborio rice) and paella (with bomba rice, which is actually an Indica variety). Cooked white rice contains 29% carbohydrate and 2% protein, with some manganese. Golden rice is a variety produced by genetic engineering to contain vitamin A.

The modern combine harvester, also called a combine, is a machine designed to harvest a variety of cultivated seeds. Combine harvesters are one of the most economically important labour-saving inventions, significantly reducing the fraction of the population engaged in agriculture. Among the crops harvested with a combine are wheat, rice, oats, rye, barley, corn (maize), sorghum, millet, soybeans, flax (linseed), sunflowers and rapeseed (canola). The separated straw (consisting of stems and any remaining leaves with limited nutrients left in it) is then either chopped onto the field and ploughed back in, or laid out in rows, ready to be baled and used for bedding and cattle feed.

The name of the machine is derived from the fact that the harvester combined multiple separate harvesting operations – reaping, threshing or winnowing and gathering – into a single process around the start of the 20th century. A combine harvester still performs its functions according to those operating principles. The machine can easily be divided into four parts, namely: the intake mechanism, the threshing and separation system, the cleaning system, and finally the grain handling and storage system. Electronic monitoring assists the operator by providing an overview of the machine's operation, and the field's yield.

A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes.

After being harvested, dry grains are more durable than other staple foods, such as starchy fruits (plantains, breadfruit, etc.) and tubers (sweet potatoes, cassava, and more). This durability has made grains well suited to industrial agriculture, since they can be mechanically harvested, transported by rail or ship, stored for long periods in silos, and milled for flour or pressed for oil. Thus, the grain market is a major global agricultural market that includes crops such as maize, rice, soybeans, wheat and other grains.

A commodity market is a market that trades in the primary economic sector rather than manufactured products. The primary sector includes agricultural products, energy products, and metals. Soft commodities may be perishable and harvested, while hard commodities are usually mined, such as gold and oil. Futures contracts are the oldest way of investing in commodities. Commodity markets can include physical trading and derivatives trading using spot prices, forwards, futures, and options on futures. Farmers have used a simple form of derivative trading in the commodities market for centuries for price risk management.

A financial derivative is a financial instrument whose value is derived from a commodity termed an underlier. Derivatives are either exchange-traded or over-the-counter (OTC). An increasing number of derivatives are traded via clearing houses some with central counterparty clearing, which provide clearing and settlement services on a futures exchange, as well as off-exchange in the OTC market.

Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, cultivars, or breeds. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals.

In animal breeding artificial selection is often combined with techniques such as inbreeding, linebreeding, and outcrossing. In plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book, On the Origin of Species. Its first chapter discusses selective breeding and domestication of such animals as pigeons, cats, cattle, and dogs. Darwin used artificial selection as an analogy to propose and explain the theory of natural selection but distinguished the latter from the former as a separate process that is non-directed.

Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

The two most common petrochemical classes are olefins (including ethylene and propylene) and aromatics (including benzene, toluene and xylene isomers).

Wheat is a group of wild and domesticated grasses of the genus Triticum (/ˈtrɪtɪkəm/). They are cultivated for their cereal grains, which are staple foods around the world. Well-known wheat species and hybrids include the most widely grown common wheat (T. aestivum), spelt, durum, emmer, einkorn, and Khorasan or Kamut. The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BC.

Wheat is grown on a larger area of land than any other food crop (220.7 million hectares or 545 million acres in 2021). World trade in wheat is greater than that of all other crops combined. In 2021, world wheat production was 771 million tonnes (850 million short tons), making it the second most-produced cereal after maize (known as corn in North America and Australia; wheat is often called corn in other countries including Britain). Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing because of the usefulness of gluten to the food industry.

A corncob, also called corn cob or cob of corn, is the hard core of an ear of maize, bearing the kernels, made up of the chaff, woody ring, and pith. Corncobs contain mainly cellulose, hemicellulose, and lignin.

The cob is not toxic to humans and can be digested, but the outside is rough and practically inedible in its original form. The foamy pith has a peculiar texture when mature and is completely bland, which most people would find unappealing, due to the consistency similar to foam plastic.

Carotenoids (/kəˈrɒtɪnɔɪd/) are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Over 1,100 identified carotenoids can be further categorized into two classes – xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons and contain no oxygen).

All are derivatives of tetraterpenes, meaning that they are produced from 8 isoprene units and contain 40 carbon atoms. In general, carotenoids absorb wavelengths ranging from 400 to 550 nanometers (violet to green light). This causes the compounds to be deeply colored yellow, orange, or red. Carotenoids are the dominant pigment in autumn leaf coloration of about 15-30% of tree species, but many plant colors, especially reds and purples, are due to polyphenols.

Barley (Hordeum vulgare), a member of the grass family, is a major cereal grain grown in temperate climates globally. One of the first cultivated grains, it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikelets and making it much easier to harvest. Its use then spread throughout Eurasia by 2000 BC. Barley prefers relatively low temperatures and well-drained soil to grow. It is relatively tolerant of drought and soil salinity, but is less winter-hardy than wheat or rye.

In 2023, barley was fourth among grains in quantity produced, 146 million tonnes, behind maize, rice, and wheat. Globally, 70% of barley production is used as animal feed, while 30% is used as a source of fermentable material for beer, or further distilled into whisky, and as a component of various foods. It is used in soups and stews and in barley bread of various cultures. Barley grains are commonly made into malt using a traditional and ancient method of preparation. In English folklore, John Barleycorn personifies the grain and the alcoholic beverages made from it. English pub names such as The Barley Mow allude to its role in the production of beer.

Sorghum bicolor, commonly called sorghum (/ˈsɔːrɡəm/) and also known as broomcorn, great millet, Indian millet, Guinea corn, or jowar, is a species in the grass genus Sorghum cultivated chiefly for its grain. The grain is used as food by humans, while the plant is used for animal feed and ethanol production. The stalk of sweet sorghum varieties, called sorgo or sorgho and taller than those grown for grain, can be used for forage or silage or crushed for juice that can be boiled down into edible syrup or fermented into ethanol.

Sorghum originated and was domesticated in Sudan, and is widely cultivated in tropical and subtropical regions. It is the world's fifth-most important cereal crop after rice, wheat, maize, and barley. It is typically an annual, but some cultivars are perennial. It grows in clumps that may reach over 4 metres (13 ft) high. The grain is small, 2 to 4 millimetres (0.08 to 0.2 in) in diameter.

A staple food, food staple, or simply staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs and generally forming a significant proportion of the intake of other nutrients as well. For humans, a staple food of a specific society may be eaten as often as every day or every meal, and most people live on a diet based on just a small variety of food staples. Specific staples vary from place to place, but typically are inexpensive or readily available foods that supply one or more of the macronutrients and micronutrients needed for survival and health: carbohydrates, proteins, fats, minerals and vitamins. Typical examples include grains (cereals and legumes), seeds, nuts and root vegetables (tubers and roots). Among them, cereals (rice, wheat, oat, maize, etc.), legumes (lentils and beans) and tubers (e.g. potato, taro and yam) account for about 90% of the world's food calorie intake.

Early agricultural civilizations valued the crop foods that they established as staples because, in addition to providing necessary nutrition, they generally are suitable for storage over long periods of time without decay. Such nonperishable foods are the only possible staples during seasons of shortage, such as dry seasons or cold temperate winters, against which times harvests have been stored. During seasons of surplus, wider choices of foods may be available.

The grain trade refers to the local and international trade in cereals such as wheat, barley, maize, rice, and other food grains. Grain is an important trade item because it is easily stored and transported with limited spoilage, unlike other agricultural products. Healthy grain supply and trade is important to many societies, providing a caloric base for most food systems as well as important role in animal feed for animal agriculture.

The grain trade began as early as agricultural settlement, identified in many of the early cultures that adopted sedentary farming. Major societal changes have been directly connected to the grain trade, such as the fall of the Roman Empire. From the early modern period onward, grain trade has been an important part of colonial expansion and foreign policy. The geopolitical dominance of countries like Australia, the United States, Canada, and the Soviet Union during the 20th century was connected with their status as grain surplus countries.

Manihot esculenta, commonly called cassava, manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America, from Brazil, Paraguay and parts of the Andes. Although a perennial plant, cassava is extensively cultivated in tropical and subtropical regions as an annual crop for its edible starchy tuberous root. Cassava is predominantly consumed in boiled form, but substantial quantities are processed to extract cassava starch, called tapioca, which is used for food, animal feed, and industrial purposes. The Brazilian farofa, and the related garri of West Africa, is an edible coarse flour obtained by grating cassava roots, pressing moisture off the obtained grated pulp, and finally drying and roasting it.

Cassava is the third-largest source of carbohydrates in food in the tropics, after rice and maize, making it an important staple; more than 500 million people depend on it. It offers the advantage of being exceptionally drought-tolerant, and able to grow productively on poor soil. The largest producer is Nigeria, while Thailand is the largest exporter of cassava starch.

The Aztecs (/ˈæztɛks/ AZ-teks) were a Mesoamerican civilization that flourished in central Mexico from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language. Aztec culture was organized into city-states (altepetl), some of which joined to form alliances, political confederations, or empires. The Aztec Empire was a confederation of three city-states established in 1427: Tenochtitlan (the capital city of the Mexica or Tenochca), Tetzcoco, and Tlacopan, previously part of the Tepanec empire, whose dominant power was Azcapotzalco. Although the term Aztecs is often narrowly restricted to the Mexica of Tenochtitlan, it is also broadly used to refer to Nahua polities or peoples of central Mexico in the prehispanic era, as well as the Spanish colonial era (1521–1821).

Most ethnic groups of central Mexico in the post-classic period shared essential cultural traits of Mesoamerica. The culture of central Mexico includes maize cultivation, the social division between nobility (pipiltin) and commoners (macehualtin), a pantheon, and the calendric system. Particular to the Mexica of Tenochtitlan was the patron god Huitzilopochtli, twin pyramids, and the ceramic styles known as Aztec I to IV. The Mexica were late-comers to the Valley of Mexico, and founded the city-state of Tenochtitlan on unpromising islets in Lake Texcoco, later becoming the dominant power of the Aztec Triple Alliance or Aztec Empire which conquered other city-states throughout Mesoamerica. It originated in 1427 as an alliance between the city-states Tenochtitlan, Texcoco, and Tlacopan to defeat the Tepanec state of Azcapotzalco, which had previously dominated the Basin of Mexico. Soon Texcoco and Tlacopan were relegated to junior partnership in the alliance, with Tenochtitlan the dominant power. The empire extended its reach by a combination of trade and military conquest. It was never a true territorial empire controlling territory by large military garrisons in conquered provinces but rather dominated its client city-states primarily by installing friendly rulers in conquered territories, constructing marriage alliances between the ruling dynasties, and extending an imperial ideology to its client city-states. Client city-states paid taxes, not tribute to the Aztec emperor, the Huey Tlatoani, in an economic strategy limiting communication and trade between outlying polities, making them dependent on the imperial center for the acquisition of luxury goods. The political clout of the empire reached far south into Mesoamerica conquering polities as far south as Chiapas and Guatemala and spanning Mesoamerica from the Pacific to the Atlantic oceans.