Primary Sector history
Agriculture has no single, simple origin. A wide variety of plants and animals have been independently domesticated at different times and in numerous places. The first agriculture appears to have developed at the closing of the last Pleistocene glacial period, or Ice Age (about 11,700 years ago).
Ancient Digging Stick
By 9000-7000 BC
In Southwestern Asia, wheat and barley were cultivated, and sheep and goats were domesticated. Dogs had been domesticated in Europe by about 10,000 BC.
Oxen Pulled Plow
Agriculture developed in parts of the Americas. Domesticated crops included beans, corn (maize), cassavas, squashes, potatoes, and peppers.
Noria / Water Whell
The open-field system of planting was common in western Europe. Village land was divided into two or three large fields, and crops were rotated in each field yearly, with one field left unplanted.
In the United States, Eli Whitney invented the cotton gin, a machine that separated fiber from seed much more quickly than people could do it by hand.
The first gasoline-powered tractors were built. They gradually replaced steam-powered tractors and draft animals in many parts of the world.
The combine harvester, which combined the cutting and threshing of grain crops, came into widespread use in California. It gradually spread to other western states. The combine reduced the amount of labor needed to harvest one hectare of wheat from 37 to 6.25 man-hours.
Agrochemicals & Monocultures
DDT was introduced, marking the beginning of agriculture's heavy use of chemical pesticides in developing countries. The U.S. banned DDT in 1972 because it was harming the environment.
Machines and increased productivity in industrialized countries sharply reduced the number of people working in agriculture. Through scientific advances and improved management techniques, farmers produced more food than ever before.
Researchers in California first spliced a gene from one organism into another, and the age of genetic engineering began. Genetic engineering offers the possibility of making plants and animals hardier, more resistant to disease, and more productive.
In developed countries, farmers began using computers to keep farm accounts; to monitor crop prices and weather conditions; to help decide when to irrigate and plant; and to automate the application of fertilizers and pesticides.