Agricultural origins and the isotopic identity of domestication in northern China

Abstract

Stable isotope biochemistry (delta(13)C and delta(15)N) and radiocarbon dating of ancient human and animal bone document 2 distinct phases of plant and animal domestication at the Dadiwan site in northwest China. The first was brief and nonintensive: at various times between 7900 and 7200 calendar years before present (calBP) people harvested and stored enough broomcorn millet (Panicum miliaceum) to provision themselves and their hunting dogs (Canis sp.) throughout the year. The second, much more intensive phase was in place by 5900 calBP: during this time both broomcorn and foxtail (Setaria viridis spp. italica) millets were cultivated and made significant contributions to the diets of people, dogs, and pigs (Sus sp.). The systems represented in both phases developed elsewhere: the earlier, low-intensity domestic relationship emerged with hunter-gatherers in the arid north, while the more intensive, later one evolved further east and arrived at Dadiwan with the Yangshao Neolithic. The stable isotope methodology used here is probably the best means of detecting the symbiotic human-plant-animal linkages that develop during the very earliest phases of domestication and is thus applicable to the areas where these connections first emerged and are critical to explaining how and why agriculture began in East Asia.

Fig. 1.

Archaeological sites where early plant or animal domestication has been proposed. ① Dadiwan. ② Baijia. ③ Jiahu. ④ Peiligang. ⑤ Cishan. ⑥ Yuezhuang. ⑦ Nanzhuangtou. ⑧ Xinglongwa. ⑨ Diaotonghuan. ⑩ Kuahuqiao. The margin between rice and millet farming is approximate. P.R.C., People's Republic of China.

Fig. 2.

The isotopic identity of domestication at Dadiwan. (A) Low δ¹³C values in wild-foraging taxa establish the dominance of C₃ plants in the landscape. (B) Positive correlation between high δ¹³C and high δ¹⁵N illustrates life within the domestic sphere. Gradation between wild and domestic illustrates the plasticity of early farming systems. Phase 1 dogs (△) within the dotted oval are the earliest examples of domestication in northwest China. Ungulates include deer (Cervus sp. and Moschus sp.) and cattle (Bos sp.) but not pigs. Birds have been tentatively identified as Gallus sp., bear as Ursus arctos (22).

Fig. 3.

Human diet during the Yangshao Neolithic at Dadiwan. As regular consumers of C₄ plants with regular access to animal products (likely including the flesh of animals that also eat C₄ plants), humans clearly reside within the domestic sphere.

Fig. 4.

A chronology of Holocene occupation and domestication at Dadiwan. This summed probability distribution of calibrated radiocarbon dates (Table S3) provides a rough proxy for occupation intensity at the site. ① Hunter–gatherers arrive at Dadiwan. ② The earliest evidence for domestication of dogs and broomcorn millet. ③ The site is largely abandoned. ④ Intensive agriculture involving dogs, pigs, broomcorn, and foxtail millet arrives with the Yangshao Neolithic. ⑤ The site is abandoned again.