Archaeobotanical studies have largely illuminated spatiotemporal differences in agricultural development across the Loess Plateau. However, the particularities of local agricultural development have not been adequately studied for complex geographical, environmental, and prehistoric contexts. Here, new archaeobotanical data and radiocarbon dating results from 27 Neolithic and Bronze Age sites in Baoji are reported. Combining these data with published archaeobotanical datasets, this study explores shifts (and underlying driving factors) in cropping patterns from the late Neolithic to Bronze Age on the southern Loess Plateau (SLP). Regional geographic, environmental, and climatic factors produced mixed millet-rice agricultural systems in the Guanzhong Plain (GZP) and western Henan Province (WHN) and foxtail and broomcorn millet dry-farming systems in the Upper Weihe River (UWR) from 5800–4500 cal BP. Wheat and barley were added to the agricultural systems of the UWR as auxiliary crops after ~4000 cal BP, while cropping patterns remained largely unchanged in GZP and WHN from 4500–3500 cal BP. Cultural exchanges and technological innovations may have influenced the formation of different agricultural patterns across the three regions (i.e., GZP, WHN, and UWR) from 4500–3500 cal BP. From 3500–2200 cal BP, wheat and barley became increasingly important crops on the SLP, although their importance varied spatially, and rice was rarely cultivated. Spatiotemporal variation in cropping patterns was driven by altered survival pressures associated with climate deterioration and population growth from 3500–2200 cal BP. This process was reinforced by internal social developments, as well as interactions with close northern neighbors, in the Shang-Zhou period.

By 4000 BP, trans-Eurasian agricultural exchanges increased across the Hexi Corridor. However, the nature and timing of many early prehistoric agricultural exchanges remain unclear. We present systematically collected archaeobotanical data from the ancient Haizang site (3899–3601 cal a BP) within the Hexi Corridor. Adding to previous archaeobotanical studies of the Hexi Corridor, we find that agricultural production transformed from purely millet-based agriculture during the Machang Period (4300–4000) to predominantly millet-based agriculture increasingly supplemented with wheat and barley during the Xichengyi and Qijia periods (4000–3600 BP). These transformations are likely due to adaption to a cooler and drier climate through cultural exchange. A warm and humid climate during 4300–4000 BP likely promoted millet agriculture, Machang cultural expansion westward, and occupation across the Hexi corridor. However, after the “4.2 ka BP cold event” people adopted wheat and barley from the West to make up for declining millet agricultural productivity. This adoption began first with the Xichengyi culture, and soon spread further eastward within the Hexi Corridor to the Qijia culture.

Agriculture is a critical foundation for the development of large-scale complex and urban societies. Sanxingdui, located on the Chengdu Plain in western Sichuan and linked with the ancient Chinese Shu Kingdom, is one of the most distinctive archaeological sites in the world. However, despite its importance, the agricultural economy of the Sanxingdui culture and the Chengdu Plain remains poorly understood and heavily debated. This study synthesizes recent archaeological and historical evidence concerning the agricultural economy underpinning the increasing scale and social complexity at Sanxingdui and the greater Chengdu Plain prior to 2200 BP. Our analysis finds a mixed rice and dry-land millet farming economy, in conjunction with pig and chicken husbandry, during the Sanxingdui culture (3700–3100 BP). This integrated agricultural system likely began with the Baodun culture (4500–3700 BP), passing to the Sanxingdui culture (3700–3100 BP), Shierqiao culture (3100–2600 BP) and later, the Shu culture (2600–2300 BP). In addition, although gathering, hunting, and fishing accounted for relatively low proportions of the overall subsistence, the ancient peoples at Sanxingdui and across the Chengdu Plain continued these practices, supporting a diverse agricultural and food system. Understanding the subsistence at Sanxingdui offers key insights into the development of complex societies in southwest China, the contributions to Chinese culture, and the role of agriculture worldwide.