AgricultureAGRICULTURE IS THE practice of cultivating plants and herding animals for food, fiber, and other products. Agriculture is the single largest land use in the world and it is the single greatest employer. Nearly 38 percent of the earth’s land area is in agriculture. In 2004, more than 2.6 billion people, or 42 percent of the world’s population, were engaged in agriculture. 10,000 years ago, only a trivial fraction of the earth’s surface was dedicated to agriculture. Since then, agriculture has replaced prairies, wetlands, forests, and other ecosystems, allowing the global population to exceed 6.3 billion. Agriculture features prominently in many debates linking environment and society. It is blamed for reducing biodiversity, polluting aquatic ecosystems with eroded soils and toxic chemicals, and contributing to global climate change. Agriculture is also at the center of the debate about genetically altered food, trade, and globalization. Developing more sustainable agricultural systems will be required to reduce the impact of agriculture on the environment and provide enough food for the projected 8 billion people who will inhabit the planet by 2036.