We report directly dated evidence from circa 1400 calibrated years (cal) B.C. for the early use of wheat, barley, and flax as staple crops on the borders of the Tibetan Plateau. During recent years, an increasing amount of data from the Tibetan Plateau and its margins shows that a transition from millets to wheat and barley agriculture took place during the second millennium B.C. Using thermal niche modeling, we refute previous assertions that the ecological characteristics of wheat and barley delayed their spread into East Asia. Rather, we demonstrate that the ability of these crops to tolerate frost and their low growing degree-day requirements facilitated their spread into the high-altitude margins of western China. Following their introduction to this region, these crops rapidly replaced Chinese millets and became the staple crops that still characterize agriculture in this area today.

Over the past two decades, environmental studies in research on prehistoric China have been gaining popularity and importance. For Northwest China in particular, climate change, especially the so-called ~4.2k BP event has been seen as the main reason for an alleged collapse of Late Neolithic societies and a transition to pastoral-heavy economies and mobile lifeways. Yet, these explanatory models tend to rely on limited archaeological and environmental data and non-contemporaneous historical data, resulting in simplistic causal relationships between environmental changes and social response. This paper re-evaluates the Incipient Bronze Age in China’s Northwestern region, discussing evidence for climate change and its exact dates, as well as textual and archaeological evidence. We argue that the old narratives perpetuating the image of a dichotomy between Steppe and Sown are inaccurate, while large-scale models of region-wide subsistence change in response to climate cooling tend to disregard local developments and group-specific responses as well as chronological issues. Focusing on the Xindian and Siwa archaeological phenomena, this paper provides a view into sub-regional responses to this climate event, warning against simplistic broad-brush reconstructions and calling for both a return to archaeological fundamentals and large-scale intensive fieldwork and interdisciplinary studies involving archaeologists, paleobotanists, zooarchaeologists, isotope specialists, and climate scientists.

The transition between the Majiayao (5300-4000 BP) and Qijia (4200-3500 BP) "cultures" in what is now northwestern China's Gansu Province has typically been defined by major technological changes in pottery forms, subsistence practices, and site locations. These changes are thought to have been driven by a combination of climate change induced cooling and drying as well as human migration into the region from areas further east. Based on our review of literature on the topic, as well as recent fieldwork in the northern Tao River Valley, we suggest that the picture is significantly more complex, with some new technologies slowly being experimented with, adopted, or rejected, while many other aspects of production and social organization persisted over hundreds of years. We hypothesize that these changes reflect the active agency of the inhabitants of southern Gansu during the fifth and fourth millennia BP balancing long-standing cultural traditions with influxes of new technologies. Unlike some societies in other regions at this time, however, increasing technological specialization does not appear to have resulted in growing social inequality, but the archaeological material instead reflects increasingly complex heterarchical organization.