China: Millet cultivation began on a small scale in 8000 BC on the northern plains as a seasonal supplement to foraging and hunting, but it did not become a staple food until 3000 years later. In the eastern forests of North America, seed crops were already present in 3000 BC, but serious agriculture did not arrive until 4000 years later, in 1000 AD. In Mexico, corn and squash were domesticated by humans through agriculture in 7000 BC. However, they did not become staples of the local diet until 5000 years later. These examples provide evidence that the path to agriculture was neither obvious nor linear and inexorable as one might think. On the contrary, Neolithic agriculture was an experiment that could and sometimes did fail.
