Relationship Between C 4 Biomass and C 4 Agriculture During the Holocene and its Implications for Millet Domestication in Northeast China

The origin of C 4 agriculture in China, foxtail millet ( Setaria italica ) and common millet ( Panicum miliaceum ), remains unclear. Here we conducted a comprehensive geochemical study of the archeological site of Chahai in Northeastern (NE) China and deduced that higher C 4 biomass in the cultural layers was mainly caused by agricultural practices and other human activities. To evaluate the anthropogenic factors involved in millet domestication, we produced a time series of contour maps of C 4 biomass for North China since 14 ka and integrated archaeological data. Results show that the origin and development of millet agriculture was nearly synchronous with the increase in C 4 biomass in the early‐mid Holocene, but the synchrony was decoupled at ∼4 ka when millet cultivation was established in NE China. Our findings suggest that both human management (possibly cultivation) of C 4 plants, and an environmental background of high C 4 biomass drove the origin of millet agriculture.