Post-Neolithic broadening of agriculture in Yunnan, China: Archaeobotanical evidence from Haimenkou

We report archaeobotanical results from systematic flotation obtained during the 2008 excavation of the site of Haimenkou, in Northwest Yunnan, dated to c. 1600-300 BCE. Haimenkou is thus far the largest prehistoric settlement excavated in Yunnan, its long occupation across the second and first millennium BCE bridges a gap from the Neolithic to the Bronze Age, and its location close to bronze smelting sites and the core area of the 1st millennium BCE polity of the Dian makes it an important site to investigate the early development of the province. It is also the earliest site with evidence for wheat and barley in Yunnan and provides essential data for tracing the spread of the two crops into Yunnan, as well as for understanding the agricultural production developments in the province from the second millennium BCE onward. People at Haimenkou were practicing a mixed-crop farming strategy based first on rice and millet, and with the addition of wheat from c. 1450 BCE. Between c. 800-300 BCE archaeobotanical remains attests to a general decrease of millet and rice production in favour of wheat, possibly linked with a drying climate. Other important cultivars present include large quantities of Chenopodium (associated with other cereal crops remains such as rice and millets), Perilla (Shisoo) seeds, and a few grains of buckwheat, all possibly utilized as crops. Additionally, Cannabis seeds have also been retrieved. Several fruits species feature in the assemblage, including peaches (Amygdalus persica), apricots (Armeniaca vulgaris), although these are present in minor quantity in relation to crops and might indicate that local plant resource collection had a secondary role to crop cultivation.