A crop is a plant or plant product grown and harvested for profit or personal subsistence. The defining characteristic is intentional cultivation, which distinguishes a crop from a wild plant that is simply gathered. This human intervention transforms a plant into a crop and is a fundamental component of agriculture, aimed at producing a specific output like food, fuel, or material.
Major Categories of Crops
Crops are classified based on their intended use. The most prominent category is food crops, cultivated for direct human consumption. This group is subdivided into cereals or grains like wheat and corn, which are grasses grown for their edible starchy seeds. Fruits are the mature ovaries of flowering plants, while vegetables consist of other plant parts like leaves, roots, and stems.
Feed crops are grown specifically for nourishing livestock. Alfalfa and certain varieties of corn and soybeans are primary examples, cultivated to provide calories and nutrients for animals in the agricultural system. These crops are an indirect part of the human food supply chain, supporting the production of meat, dairy, and eggs.
Fiber crops are cultivated for their fibrous material, used to manufacture textiles, rope, and paper. Cotton is the most well-known fiber crop, with its soft fibers spun into thread and woven into fabric. Other examples include flax, which produces linen, and hemp, used for various textiles and industrial materials.
Industrial crops are grown for purposes other than food, feed, or fiber. This category includes plants cultivated for biofuel production, such as switchgrass or corn processed to create ethanol. It also encompasses crops grown for their oils, like rapeseed, or for chemical compounds used in manufacturing, such as rubber.
The Role of Crops in Human Civilization
Crop cultivation has been a foundational element in developing human societies, shaping economies and daily life. A small number of plant species, known as staple crops, form the basis of the global food supply. Rice, wheat, and maize (corn) are the most significant staples, providing the majority of the world’s food energy. The reliability and high-yield nature of these crops allow for the sustenance of large populations, supporting food security.
Many crops are grown as cash crops, primarily for sale on the market rather than for use by the farmer. These crops, such as coffee, cocoa, tobacco, and sugarcane, are often grown in developing nations and exported. The trade of cash crops can be a major driver of local and national economies, providing income and employment for millions.
The production and sale of staple and cash crops influence international relations, trade policies, and economic stability. Fluctuations in the yield or price of a major crop like wheat or coffee can have ripple effects across the world. These changes affect consumer food prices and the economic health of nations that depend on agricultural exports.
From Wild Plant to Cultivated Crop
The journey from a wild plant to a cultivated crop is the result of domestication. This process began thousands of years ago when early humans started to favor and selectively propagate wild plants with desirable characteristics. This selection was a gradual development occurring over many generations of plants and people.
Through selective breeding, humans guided the evolution of these plants to better suit their needs. Traits such as larger seeds or fruits, higher yields, and structural changes that made harvesting easier were consistently chosen. For example, in wild grains, the seed heads often shatter to disperse seeds, but farmers selected for plants where the seeds remained attached, simplifying collection.
This process altered the genetic makeup of the plants, creating new varieties that were often dependent on humans for their survival. The development of these cultivated crops allowed the transition from nomadic lifestyles to settled agricultural communities. This shift enabled the growth of villages, cities, and civilizations.