Farms grow crops and raise animals. As of 2023, total U.S. farm output had nearly tripled since 1948. The number of U.S. farms peaked at 6.8 million in 1935 and then fell sharply until the early 1970s. As of 2024, the United States had 1.88 million farms, down 8 percent from the 2.04 million in the 2017 Census of Agriculture. In the early 1900s an average U.S. farmer produced enough food to feed a family of five, and many of today's farmers can feed that family and about 100 other people.
During the 1950s and 1960s, scientists created types of wheat and rice that were easier to grow and introduced them into Mexico and parts of Asia; this is called the Green Revolution. Norman Borlaug developed a robust dwarf wheat strain adapted to Mexican conditions, and by 1956 Mexico was self-sufficient in wheat. In the mid-1960s Borlaug introduced dwarf wheat into India and Pakistan, and production increased enormously.
Wheat, corn (maize) and rice are grains that people around the world grow and eat, and flour for bread comes from wheat grain. An average 60-pound bushel of wheat yields about 45 pounds of flour (75 percent) and 15 pounds of millfeed (25 percent) at the mill. Some crops, such as oats and alfalfa, are grown to feed farm animals.
A crop depends on the soil beneath it. Plants grow in soil, which gives them water, nutrients and support, and soil is made of mineral particles, organic matter, water and air. In the early 1800s, scientists discovered that nitrogen, phosphorus and potassium were the most important nutrients for growing plants. You may have heard that soil is just dirt with nothing alive in it. In fact, soil is a living ecosystem with bacteria, fungi, worms and insects in it. A gram of surface soil can contain approximately 100,000,000 bacteria, and a cubic yard can hold up to 1,000 earthworms, which help break down dead plant material.
Crop rotation means growing a series of different crops in the same field over the seasons. It helps break the cycle of pests and disease that builds up when one crop is grown again and again. Studies show yield increases of 10 to 15 percent in soybeans and corn when crops are rotated. In the open-field system of medieval Europe, one field was planted in spring, another in autumn, and one was left unplanted, or fallow.
Many crops depend on pollination. Pollen carries a plant's male cells, and pollination helps a plant make seeds. Virtually all of the world's seed plants need to be pollinated, and of the 1,400 crop plants grown around the world, almost 80 percent require pollination by animals, as of November 2026. You may have heard that bees only matter because they make honey. Bees also help fruits, nuts and other foods grow by visiting flowers. Bees make honey from the nectar of flowers, and honey bees make honey to store as food for the winter.
A dairy farm milks cows to get milk. On a dairy farm, milk is cooled as soon as possible, collected in a bulk tank and then transported to a processor. Pasteurization is a heating process that kills potential pathogens in raw milk. Louis Pasteur, a French chemist and microbiologist, first came up with pasteurization for beer and wine to keep them from souring. Milk is then bottled or made into ice cream, cheese or other products, refrigerated and distributed.
Cooling fresh produce right after harvest helps it stay good for longer. Cooling fresh produce lowers its rate of respiration, which can significantly increase shelf life. In the United States, eggs are cleaned and kept cold after hens lay them. The cold chain is a series of refrigerated cooling, storage and transport steps that keeps food at the right temperature from grower to consumer.
Words to know
- strain: plant variety
- revolution: big change
- pasteurization: heating raw milk
- pollination: seed-making help
- fallow: left unplanted
