The first evidence of agriculture appears in the archaeological record some 10,000 years ago. But the skills needed to cultivate and harvest crops weren’t learned overnight. Scientists have traced these roots back to 23,000-year-old tools used to grind seeds, found mostly in the Middle East.
Now, research lead by Li Liu, a professor of Chinese archaeology at Stanford, reveals that the same types of tools were used to process seeds and tubers in northern China, setting China’s agricultural clock back about 12,000 years and putting it on par with activity in the Middle East. Liu believes that the practices evolved independently, possibly as a global response to a changing climate.
The earliest grinding stones have been found in Upper Palaeolithic archaeological sites around the world. These consisted of a pair of stones, typically a handheld stone that would be rubbed against a larger, flat stone set on the ground, to process wild seeds and tubers into flour-like powder.
Once the stones are unearthed, use-wear traces and residue of starch grains on the used surfaces can be analysed to reveal the types of plants processed.