To reveal the relationship between millet-based agriculture and new productivity factors (cattle and sheep husbandry) on the northwest edge of the Loess Plateau during c. 4000 a BP and explore the motivation of social complexity development, stable carbon and nitrogen isotope analyses of human (n = 3) and faunal (n = 53) bones from the Bicun site, Xing county, Shanxi, China, were undertaken. The results show that some humans (–7.3‰, 8.8‰, n = 1), pigs (–7.9 ± 1.7‰, 5.9 ± 0.7‰, n = 15), and dogs (–7.8 ± 0.3‰, 7.5 ± 0.4‰, n = 2) mainly lived on millet-based food, while other humans (–13.4 ± 0.2‰, 6.7 ± 1.0‰, n = 2), cattle (–13.9 ± 1.3‰, 5.6 ± 0.6‰, n = 11), and sheep (–16.0 ± 1.1‰, 5.3 ± 0.7‰, n = 15) lived on C3/C4 mixed food. Cattle and sheep not only grazed in wild ecosystems but also ate millet and its byproducts as fodder. Many deep gullies and ravines on the northwest edge of the Loess Plateau are not suitable for the development of millet agriculture but are the ideal pasture for herding cattle and sheep, which undoubtedly promoted material productivity. Instead of encroaching on the development of pig feeding, cattle and sheep husbandry made the utilization of millet-based food more effective. However, wheat and barley did not affect the diets of humans and animals. A new economic mode with millet-based agriculture and new productivity elements provides a solid material foundation for the great development of archaeological cultures and social complexity on the northwest edge of the Loess Plateau during c. 4000 a BP.

Bicun site,,c. 4000 a BP,Carbon and nitrogen stable isotopes,Millet agriculture,Herding sheep and cattle