Palaeoecological and historical evidence for manuring and irrigation at Garðar (Igaliku), Norse Eastern Settlement, Greenland

Palaeoenvironmental data are presented from the site of Gardar (modem Igaliku), the location of the cathedral and the bishop's farm in the Norse Eastern Settlement of Greenland. The latter was founded from c. AD 98 5 and abandoned some time during the fifteenth century. Inspection of drainage ditches located in close proximity to the settlement ruins revealed inter alia an organic-rich unit containing cultural debris (worked wood, animal bone, stone and charcoal) dated by AMS radiocarbon dates on seeds to the period C. AD 1110-1370. Fossil insect and pollen assemblages contained within the deposit appear representative of natural environments (primarily wet eutrophic meadows) but are mixed with high frequencies of a range of synanthropic insects, including human and animal ectoparasites that could only derive from indoor habitats. This is strongly indicative of the manuring of fields with waste from houses and bytes in order to increase yields of hay. Large amounts of hay would have been necessary to provide winter fodder for the bishop's herd of cattle the largest known in Norse Greenland - and dung from these animals seems likely to have been a significant component of the material used to fertilize the fields. The process of spreading the manure at Gardar was probably integrated with the careful manipulation of water resources across the site, indicated by the presence of a network of irrigation channels and dams in the archaeological record, and comparisons are drawn with similar systems elsewhere in Mediaeval Europe.