Abstract: A trencher plow for laying pipe such as drainage pipe which includes in combination an auger angled downwardly toward a plow which follows, both mounted in a superstructure and being arranged to be cooperatively raised and to set the grade and depth of cut by the plow determinable by sensing the grade setting signal of a laser unit located in the field of cut. The auger is provided with cutting lobes distributed about its teeth which facilitate cutting and throwing soil to the sides of a trench being dug in advance of the plow which finalizes shaping of the trench for deposition of pipe into the trench.

Abstract: A method and apparatus in which a disk-type ditcher adaptable to being drawn by a tractor can dig ditches under control of a laser system by which a desired ditch grade can be selected. The ditcher incorporates a disk rotatable in a generally vertical plane transverse to the line of travel of the ditcher, the disk having circumferentially spaced scoops which during rotation function in cooperation with a bottom-cutting blade and soil plowing section to lift the cut soil for discharge from an angularly oriented overlying chute for directing soil particles a pre-selected lateral distance from the line of travel of the tractor. A pair of forwardly and oppositely positioned angularly adjustable side cutting or scraping blades can be provided in spaced relation on opposite sides of the center line of travel to impart steeper side walls to the ditch than would otherwise be formed with the circular disk alone.