Environmental changes and ancient long-term wet field management schemes: A preliminary case study of the Daepyeongri site, locality 3-1-D, South Korea

Abstract

Large-scale excavations between 2012 and 2015 at the Daepyeongri site on the floodplain of the River Geumgang have revealed the presence of an ancient complex settlement comprising houses, extensive agricultural fields, and pits that have been dated to between the Bronze Age and the early Three Kingdoms periods. The beginning and end of the occupation of this site and land-use patterns are assumed to have been associated with its natural environment. The pollen records presented in this study show that wet conditions continued throughout the time that this site was occupied, evidenced by the consistent appearance of Alnus, while there are nevertheless hints of some land reclamation from the Bronze Age onwards. More intensive agricultural activities that took place during this later period are evidenced by an increase in the abundance of NAP pollens related to cultivation including Gramineae, Cyperaceae, Bistorta, Compositae and Fagopyrum. At the end of the occupation period, an abrupt transition to wetter conditions is recognized while dry land condition had been prevalent for some time in other parts of the site. Microscopic examination of buried cultivated soils that evidence multiple phases of ancient field systems has enabled the identification of pedological traces of discrete cultivation patterns and shows that they changed over time. The recognition of micro-structures and associated features shows that seasonally flooded wetland was first utilized during the early phase (the Bronze Age), and that more intensified irrigation management was seen during the late phase (the time span encompassed by the proto-Kingdoms and Three Kingdoms periods). These data reveal evidence for intensive hydromorphic degradation and enable a robust recognition of settlement history and an enhanced understanding of the intensity of various land-use patterns, and landscape changes from both environmental and archaeological perspectives.