Early Island rice farmers on the South China Coast during the 7th millennium BP

The spread of agriculture and population from Mainland East Asia to the islands of Southeast Asia and Oceania was the last far-reaching prehistoric phenomenon in the Pan-Pacific region. However, archaeobotanical data examining whether and when early rice farmers occupied these islands is limited and thus contested. Thus, we performed phytolith, OSL and radiocarbon dating analyses of two Neolithic shell mound sites on Haitan Island on the South China Coast. The new dates were amalgamated with the results of earlier absolute dating studies, providing a chronology for these sites. Our results indicate that the two occupation peaks of the Keqiutou Culture centred between approximately 6800–6300 cal BP and 5800–5300 cal BP. Continuous rice phytolith records—including rice bulliforms—were observed in the Neolithic layers at the two sites. Moreover, rice bulliform phytoliths with ≥9 fish-scale decorations accounted for 41%, higher than the established standard for wild rice, suggesting that rice cultivation had already emerged at 6800 cal BP on Haitan Island and probably earlier. These findings provide the earliest evidence of rice cultivation on Haitan Island, adding evidence of the first farmers’ sea voyages and colonisation of the South China Coast islands.