Rice cultivation spread north 5,800 years ago

"Phytolith analysis of residue found at the Dongyang site can help separate different tissues of the plants so as to analyze the farming conditions in a specific age," said Wu Yan, research associate of the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology.

"We also found phytoliths of rice leaves, husks and straws, a complete chain of rice-growing," she added.

Xu Weihong, a researcher with the Shaanxi Provincial Institute of Archaeology, said "Research indicates that rice comes from local farming rather than from trade or exchange."