Understanding the Collapse of the Longshan Culture (4400-3800 BP) and the 4.2 ka Event in the Haidai Region of China – from an Agricultural Perspective

The Haidai region was important for early Chinese cultures that reached their prehistoric peak during the Longshan period (4400–3800 BP). However, the continuous development of Longshan societies was interrupted from the Yueshi period (3800–3600 BP) in West-Haidai but in the Late Longshan phase (4100/4000–3800 BP) in East-Haidai. As archaeobotanical data has accumulated, a comprehensive study on agriculture over this time has become feasible, one which is quite sensitive to climate change and also crucial to human society. Therefore, we conducted a synthetic analysis of macro-botanical remains from 25 Longshan sites using Representativeness Index (RI) and Correspondence Analysis (CA). We identified sub-regional differences in crop structures and cultivation regimes between West- and East-Haidai that offer new insights into social changes that arose after the 4.2 ka BP event. While facing abrupt cooling and drought, societies engaged in millet farming in West-Haidai exhibited stronger resilience than those in East-Haidai that were occupied primarily with rice farming. Moreover, to cope with environmental deterioration, West-Haidai inhabitants may have attempted to change cropping practices by exploiting previously uncultivated lands whereas those in East-Haidai were preoccupied with intensive rice farming throughout the entire Longshan period and probably mitigated food shortages by population migration.