Soils and palaeo-climate based evidence for irrigation requirements in Norse Greenland

Establishing and sustaining agricultural production was a key factor in the success of Norse settlements during the landnám colonisation across the North Atlantic. In light of the occurrence of channel features in several abandoned home-field areas of the Norse Eastern Settlement of Greenland, and the irrigation requirements of present-day Greenlandic sheep-farmers questions are raised: was irrigation used by the Norse settlers of Greenland on their home-field areas? and, if so, how frequently? Modelling of soil chemical, physical and soil-water hydraulic properties integrated with contemporary high-resolution climatic data demonstrate a frequent requirement for irrigation. Soil moisture deficits are related to the duration and intensity of winter temperature. Using the winter Dye 3 ice core δ18O record as a climatic proxy, the frequency of moisture deficits, based on comparing mean winter temperatures, indicates that there was a frequent irrigation requirement to maintain home-field productivity, increasing throughout the period of settlement until the 14th Century.