ABSTRACT Prior to the construction of a highABSTRACT-speed railway track (TGV) between Antwerp (Belgium) and the Dutch border, archaeological and geoarchaeological research was conducted at several archaeological sites. All are situated in the northern Campine, a region characterised by quartz-rich, nutrient-poor cover sands. On the site of Brecht-Zoegweg, two well preserved deepened byres (‘potstallen’) were uncovered in Roman stable-houses. Stables with sunken floors are commonly recorded on Roman-period farms in the sandy part of northern Belgium. Following medieval to sub-recent parallels in the area, they are considered to be features serving agricultural fertilising purposes through the intentional accumulation of dung and the creation of manure by mixing with added organic matter (sods or ‘plaggen’). This archaeopedological research investigates several questions concerning the origin and the infill process of these remarkable features. Field observations, analytical and micromorphological data point to a gradual succession of events leading to a byre with a sunken floor, rather than an intentional digging out of the floor concomitant with the house construction and a post-occupational filling or levelling. It is furthermore suggested that plaggen fertilisation could indeed have been applied, at least in some of the phases of the byre use. ; This article is part of a book edited at the occasion of the Geoarchaeological meeting of Bruges: Soils as records of Past and Present: the geoarchaeological approach. Focus on: is there time for fieldwork today? - Bruges (Belgium), 6 and 7.11.2019. Editors Judit Deák, Carole Ampe and Jari Hinsch Mikkelsen Technical editor Mariebelle Deceuninck English language reviewer Caroline Landsheere Graphic design Frederick Moyaert Printing and binding Die Keure, Bruges