Phytolith records of rice agriculture during the Middle Neolithic in the middle reaches of Huai River region, China

The Shunshanji site is one of the earliest archaeological sites identified in the middle reaches of Huai River region. Using phytolith analysis, 66 samples from 3 exposed profiles at the Shunshanji site were studied in order to contribute to the understanding of the nature of rice remains at the site and early farming information in the middle reaches of the Huai River region of China. The presence of rice phytoliths possibly from domesticated rice (Oryza sativa) in a sequence of sediments from Shunshanji site suggests that rice had been used and cultivated at Shunshanji, while dry farming had not reached the area between 8500 and 7000 BP. In addition, the continuous occurrence of a large percentage rice phytoliths that fall into wild or intermediate types and some domesticated rice phytoliths increased in percentage through time indicate the rice domestication was in the early stage, and the selective pressure changed the phytoliths morphologies gradually with time. This paper provides new evidence for understanding the origin and early development of rice agriculture in the Huai River region, and some clues for discovering the temporal-spatial route for the northward spread of rice cultivation and southward spread of dry farming in China.