Archaeological excavations have finally answered questions regarding the age and development of prehistoric fields enclosed by earthen ridges, known in the Netherlands as 'Celtic fields'.
     Using Optically Stimulated Luminescence, a technique that dates the last exposure to light or heat sources of quartz minerals, archaeologist Stijn Arnoldussen from the University of Groningen determined that banks around the later prehistoric field plots were constructed more than 3100 years ago, and remained in use for hundreds of years.
     Arnoldussen's research indicates the banks were constructed of sods taken from wet heathlands or stream valleys, brought to the settlements, mixed with dung and domestic refuse, and taken back to the field plots as manure. Uprooting field weeds and discarding them at the field's edges gradually came to form banks between fields.
     Arnoldussen says the fields are one of the most extensive and still visible types of archaeology in the Dutch landscape. The field complex investigated by the Groningen Institute of Archaeology at Lunteren measured at least 210 hectares in prehistory.
     The banks were constructed around 1100 BCE, but were still increasing in height 700 years later, representing an agricultural landscape of unprecedented stability and durability. Palaeobotanical analyses showed that barley, wheat and flax were cultivated.
     "We now know the age of several banks in two Dutch Celtic fields, yet the precise ways in which the Celtic field agriculture was executed (crop rotation, fallow period, and interspersed occupation) and whether Celtic fields in other parts of the Low Countries are similar, remains unclear", says Arnoldussen. This summer he will excavate another Celtic field, this time within the coversand landscapes of the Southern Netherlands.

Edited from Past Horizons (23 March 2014)