Direct isotopic evidence for human millet consumption in the Middle Mumun period: Implication and importance of millets in early agriculture on the Korean Peninsula

It is generally believed that early agriculture on the Korean Peninsula was established during the Mumun period (1500–100 BC). While previous studies on agriculture in prehistoric Korea have relied on cultivated plant remains from archaeological sites, only a few isotopic studies have been conducted on Mumun individuals due to poor bone preservation during this period. Here, we measured bulk carbon (δ13C) and nitrogen (δ15N) stable isotope ratios as well as individual amino acid δ13C results (δ13CAA) of collagen from human (n = 7) and animal (n = 4) bones from three Mumun sites (Hwangsok-ri, Jungdo, Maedun Cave) in the central inland portion of South Korea. The aims of this study were to explore the contribution of plant foods to the human diet and to examine the type and extent of agriculture in the Mumun period. In contrast to the surrounding C3 vegetation, all the Mumun humans in this study had significantly 13C-enriched results, evidence for the consumption of C4 plants (foxtail and broomcorn millet). The δ13CAA data show that there was no consumption of freshwater or marine resources in the diet of the Mumun. These data indicate that C4 plants (millets) were the main dietary sources in central inland South Korea and that millet agriculture was fully established during the Middle Mumun period. This finding highlights the importance of millet cultivation during the Mumun period and provides a revaluation for the significance of millets in the development of early agriculture on the Korean Peninsula. •Bronze Age Mumun individuals consumed C4 plants (foxtail and broomcorn millet.•Results counter the current emphasis of rice farming during the Mumun period.•Findings provide a reevaluation of millets in early agriculture on Korean Peninsula.