n.
Science or art of cultivating the soil , growing and harvesting crops , and raising livestock .
Agriculture probably first developed in South Asia and Egypt, then spread to Europe, Africa, the rest of Asia, the islands of the central and South Pacific, and finally to North and South America. Agriculture in the Middle East is believed to date from 90007000 BC. Early cultivated crops include wild barley (Middle East), domesticated beans and water chestnuts (Thailand), and pumpkins (the Americas). Domestication of animals occurred during roughly the same period. Slash-and-burn landclearing methods and crop rotation were early agricultural techniques. Steady improvements in tools and methods over the centuries increased agricultural output, as did mechanization, selective breeding and hybridization, and, in the 20th century, the use of herbicides and insecticides . More of the world's aggregate manpower is devoted to agriculture than to all other occupations combined.