Stable isotope analysis of humans from Xiaojingshan site: implications for understanding the origin of millet agriculture in China

Millet agriculture originated in Northern China in the early Neolithic period (ca. 8000 BP), however, the actual importance of millet in human diets is still not clear. To determine the relative contribution of millet in human diets in this period we undertook stable isotope analysis of humans from Xiaojingshan site and fauna from Yuezhuang site, both of which are attributed to the Houli Culture and date to about 8000 years ago. The carbon isotope values of human bone collagen showed that millet (as a C₄ plant) only contributed approximately 25% of dietary protein, with the rest from C₃ based plant and animal sources, if a simple mixing model is used. We did not observe any statistical dietary difference between males and females at the site, although it has been argued that the Houli Culture was a matriarchal society. Finally, we compared our data with other published isotopic data from the contemporary Jiahu site and Xinglongwa site and a number of sites from the subsequent Yangshao Culture and found that millet only became a significant source of dietary protein approximately 1000 years later, as human carbon isotope values from these later sites indicated that almost all of dietary protein came from C₄ (i.e. millet) sources.