Thousands of years ago, people began farming the land to grow grain crops, such as wheat, and rearing animals for their meat, milk, and other products. Today, many farmers use modern techniques and equipment to produce bumper crops.
Middle Eastern farmers began rearing herds of sheep and goats around 10,000 years ago. The most common domesticated animals today are cattle, sheep, and pigs. However, a wide range of animals, including deer, rabbits, ducks, turkeys, and even ostriches are now reared for their meat, milk, or eggs.
Today’s crops are descended from wild plants that produced seeds or fruits that could be eaten. Early cereal crops had small grains and therefore produced low yields. However, centuries of selective breeding (saving and sowing the best seeds) have produced large-grained varieties that give much higher yields.
Staple foods form the main part of people’s daily diet. They include the cereal crops wheat, corn, and rice. Wheat is eaten by around 35 percent of the world’s population every day. The grain is eaten whole or ground into flour, which is then used to make bread or pasta. Corn is grown in temperate, tropical, and subtropical countries. It is eaten as a vegetable, ground into flour or cornmeal, or used to make cooking oil.
Over 90 percent of the world’s rice is grown in Asia and eaten by the people living there. Rice is also grown in the United States, mainly for export. In the United States, growing rice is highly mechanized. In Asia, the work of sowing, planting out the seedlings, and harvesting is usually done by hand.
Modern combines perform two jobs: harvesting cereal crops and threshing the grain to separate the husks containing the seeds from the stems. Farmers use different machines to plow, sow, and reap, and to spray fields with fertilizers and chemicals to control weeds and pests.
Many farmers spray fields with chemical pesticides and use chemical fertilizers to protect and enrich their crops. Organic farmers prefer to use natural farming methods. They enrich the soil with manure, compost, or seaweed, and use pest-eating insects or companion planting (for example, planting onions with carrots to reduce such pests as carrot fly). Organic farmers also allow pigs and chickens to roam in fields or yards instead of keeping them in crowded pens or cages.