Abstract: An assembly for attachment to a tractor having rotatable elements which will form water collecting and retaining pockets in the ground surface being traversed thereby preventing or reducing water erosion, wind erosion and retaining water for penetration into the soil. The assembly also includes a leveller assembled in front of the tractor to level the uneven terrain created by a previous formation of water retaining pockets. The assembly for forming water retaining pockets includes a plurality of disc-like elements having a substantially semi-circular cut-out to form a pair of diametrically opposed concave soil penetrating, cutting and lifting elements rotatable about an axis inclined in relation to the direction of travel so that water retaining pockets will be formed in the ground surface at regular intervals and the soil that is removed to form the pockets will be dumped on the ground surface adjacent the pockets thus resulting in bumps or humps.