Around 10,000 years ago, as the Pleistocene gave way to our current geological epoch, a group of hunter-gathers near China’s Yangtze River began changing their way of life. They started to grow rice.Remarkably, archaeologists have now unearthed bits of this rice at a site called Shangshan. The grains, of course, were eaten long ago and the plant stalks have long been rotten, but one tiny part of rice remains even thousands of years later: phytoliths, or hard, microscopic pieces of silica made by plant cells for self-defense.
Rice leaves have fan-shaped phytoliths that don’t burn, digest, or decompose. It’s specific patterns on these phytoliths that suggest people in Shangshan were not just gathering rice, but actually cultivating it 10,000 years ago—a transition that would profoundly shift the human diet to the point where half of the world relies on the staple crop today.Chinese archaeologists began excavating Shangshan in the early 2000s.
They quickly found evidence of a rice-dependent diet: rice husks buried in pottery shards and stone tools that looked like they were used for milling. But far more abundant than artifacts are phytoliths, which are ubiquitous, if microscopic, in soil. Less than a tenth of an ounce of soil might yield thousands of phytoliths, says Dolores Piperno, a phytolith expert at the Smithsonian who was not involved in the study.