the fertile loess soils in this region of north germany are dissected by a host of brooks and headstreams, which used to flow in marshy v-shaped valleys. not all "sieke" are or were, however, crossed by a stream, but at the very least they always consisted of wet ground. during the course of medieval and early modern cultural and agricultural history, people developed these natural landforms by cutting into the edges of the v-shaped valleys (so-called "wiesenbrechen" by "wiskenmaker" ) and turning them into trough and box valleys, and any streams were regulated such that they ran in straight beds along the edges of such a box valley. the aim of these measures was the create a wet grassland in the now broad, accessible stream meadows which could then be extensively cultivated. in addition the cut, grass sods or "plaggen" were able to be used to fertilise the surrounding fields ("plaggendüngung"). in ravensberg land, "sieke" are generally narrow, trough valleys interspersed in the countryside and lying next to cultivated areas of slightly higher ground or "kuppen" ("plaggenesche"), which were raised by the grass sod fertilisation.