In the early 1900s, an average farmer in the U.S. produced enough food to feed a family of five. Many of today’s farmers can feed that family and a hundred other people. How did this great leap in productivity come about? It happened largely because of scientific advances and the development of new sources of power.
By the late 1950s, most farmers in developed countries were using both gasoline and electricity to power machinery. Tractors had replaced draft animals and steam-powered machinery. Farmers were using machines in almost every stage of cultivation and livestock management.
Electricity first became a power source on farms in Japan and Germany in the early 1900s. By 1960, most farms in the U.S. and other developed countries were electrified. Electricity lit farm buildings and powered such machinery as water pumps, milking machines, and feeding equipment. Today, electricity controls entire environments in livestock barns and poultry houses.
Traditionally, farmers have used a variety of methods to protect their crops from pests and diseases. They have put herb-based poisons on crops, handpicked insects off plants, bred strong varieties of crops, and rotated crops to control insects. Now, almost all farmers, especially in developed countries, rely on chemicals to control pests. The definition of “pest” ranges from insects to animals such as rabbits and mice, as well as weeds and disease-causing organisms—bacteria, viruses, and fungi. With the use of chemicals, crop losses and prices have declined dramatically.
For thousands of years, farmers relied on natural fertilizer—materials such as manure, wood ash, ground bones, fish or fish parts, and bird and bat waste called guano—to replenish or increase nutrients in the soil.
In the early 1800s, scientists discovered which elements were most essential to plant growth: nitrogen, phosphorus, and potassium. Later, fertilizer containing these elements was manufactured in the U.S. and in Europe. Now, many farmers use chemical fertilizers with nitrates and phosphates because they greatly increase crop yields.
However, pesticides and fertilizers have come with another set of problems. The heavy reliance on chemicals has disturbed the environment, often destroying helpful species of animals along with harmful ones. Chemical use may also pose a health hazard to people, especially through contaminated water supplies. Agricultural scientists are looking for safer chemicals to use as fertilizers and pesticides. Some farmers use natural controls and rely less on chemicals.