Transition of human diets and agricultural economy in Shenmingpu Site, Henan, from the Warring States to Han Dynasties

Historical records and archaeological remains indicate that the Chinese agricultural economy changed significantly from the Warring States (475-221 BC) to Han Dynasties (206 BC-220 AD), i.e., from rice-millet based agriculture to rice-millet-wheat based agriculture. However, the variation of human diets and the inner relationship between human diets and the agricultural transition during this period remain poorly understood. In this paper, the C and N stable isotopes from human and animal bones at the Shenmingpu site (SMPS), Xichuan County, Henan Province were analyzed. If some outliers (M34, M36, M102) were excluded, the mean delta C-13 value ((-16.7 +/- 0.8)parts per thousand, n=15) of humans in Han Dynasties was dramatically lower than that in the Warring States ((-12.7 +/- 0.8)parts per thousand, n=14), indicating that the cultivation of rice and wheat, especially wheat, had been more widely popularized in Han Dynasties. Meanwhile, the range of delta N-15 values of humans (6.6 parts per thousand-9.3 parts per thousand) in Han Dynasties was narrower than that of the Warring States (6.2 parts per thousand-10.4 parts per thousand), suggesting that the animal protein resources in human foods during Han Dynasties were more concentrated. The transition of human diets and the close relationship with the change of agricultural economy in SMPS were due to more stable society, the carryout of new agricultural policies, and the emergence of new agricultural tools in Han Dynasties.