Slab to separate cultivated and non-cultivated soil layers - has basin-shape with channels or projections down sides for excess water drainage

摘要

The slab separates the upper, cultivated layer of soil to which fertilizer has been added, from the lower layers of soil and prevents the treated soil from being washed downwards. The rectangular basin shaped slab has sides on which are vertical ducts (2) down which excess water flows from the slab. On the top of the walls of the slab are notches (3) in which are placed temp.-conditioning pieces for the cultivated soil. Instead of vertical grooves (2), the slab sides may have projections to provide a gap between adjacent slabs.