Crop in the context of "Cash crop"

Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. It corresponds roughly to the territory of modern Iraq and forms the eastern geographic boundary of the modern Middle East. Just beyond it lies southwestern Iran, where the region transitions into the Persian plateau, marking the shift from the Arab world to Iran. In the broader sense, the historical region of Mesopotamia also includes parts of present-day Iran (southwest), Turkey (southeast), Syria (northeast), and Kuwait.

Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It has been identified as having "inspired some of the most important developments in human history, including the invention of the wheel, the planting of the first cereal crops, the development of cursive script, mathematics, astronomy, and agriculture". It is recognised as the cradle of some of the world's earliest civilizations.

The Fertile Crescent (Arabic: الهلال الخصيب al-hilāl al-ḵaṣīb) is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Israel, Jordan, Lebanon, Palestine, and Syria, together with northern Kuwait, south-eastern Turkey, and western Iran. Some authors also include Cyprus and northern Egypt.

The Fertile Crescent is believed to be the first region where settled farming emerged as people started the process of clearance and modification of natural vegetation to grow newly domesticated plants as crops. Early human civilizations such as Sumer in Mesopotamia flourished as a result. Technological advances in the region include the development of agriculture and the use of irrigation, of writing, the wheel, and glass, most emerging first in Mesopotamia.

A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources or by hunting game. This is a common practice among most vertebrates that are omnivores. Hunter-gatherer groups, usually a few dozen people, were and are nomadic or semi-nomadic. Hunter-gatherer societies are contrasted with more sedentary agricultural societies, which rely mainly on cultivating crops and raising domesticated animals for food production.

Hunting and gathering emerged with Homo erectus about 1.8 million years ago and was humanity's original and most enduring successful competitive adaptation in the natural world, occupying at least 90 percent of human (pre)history. Following the invention of agriculture, hunter-gatherers who did not change were displaced or conquered by farming or pastoralist groups in most parts of the world. In Western Eurasia, farming and metallurgical societies gradually replaced hunter-gatherers, but dense forests remained their last refuge until Bronze and Iron Age societies fully overcame them.

The Neolithic Revolution, also known as the First Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period in Afro-Eurasia from a lifestyle of hunting and gathering to one of agriculture and settlement, making an increasingly large population possible. These settled communities permitted humans to observe and experiment with plants, learning how they grew and developed. This new knowledge led to the domestication of plants into crops.

Archaeological data indicate that the domestication of various types of plants and animals happened in separate locations worldwide, starting in the geological epoch of the Holocene around 11,700 years ago, after the end of the last Ice Age. It was humankind's first historically verifiable transition to agriculture. The Neolithic Revolution greatly narrowed the diversity of foods available, resulting in a decrease in the quality of human nutrition compared with that obtained previously from hunting and foraging. However, because food production became more efficient, it released humans to invest their efforts in other activities and was thus "ultimately necessary to the rise of modern civilization by creating the foundation for the later process of industrialization and sustained economic growth".

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.

Agricultural land is typically land devoted to agriculture, the systematic and controlled use of other forms of life—particularly the rearing of livestock and production of crops—to produce food for humans. It is generally synonymous with both farmland or cropland, as well as pasture or rangeland.

The United Nations Food and Agriculture Organization (FAO) and others following its definitions, however, also use agricultural land or agricultural area as a term of art, where it means the collection of:

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals (including humans). In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolian) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

Human activities have increased by 10–50 times the rate at which erosion is occurring world-wide.Excessive (or accelerated) erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and (on natural landscapes) ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses. Water and wind erosion are the two primary causes of land degradation; combined, they are responsible for about 84% of the global extent of degraded land, making excessive erosion one of the most significant environmental problems worldwide.

A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. While each plant or crop has a specific growing season that depends on its genetic adaptation, growing seasons can generally be grouped into macro-environmental classes.

Axial tilt of the Earth inherently affect growing seasons across the globe.