A slitting or tenching tool is described comprising a blade adapted to be lowered vertically into the soil and pulled therethrough so as to define a slit or trench having a depth determined by the mean depth to which the blade penetrates the soil, in which a vibrator causes the blade to vibrate at least in a generally up and down manner at the same time as it is moved in a forward direction. A second blade may be provided which is oscillated in a backwards and forwards manner. The second blade includes wings at its lower end to form a horizontal slit which communicates with the vertical trench or slit formed by the first blade. The second blade may be hollow so that finely divided particulate material may be dispensed therethrough into the trench for backfilling. A pipe or cable dispensing leg may be associated with the blades or situated between them. A tape may be fed into the horizontal slit formed by the second blade. Backfilling may be performed both above and below the horizontal slit which contains the tape. Methods of subsoiling cable and pipe laying with and without marking tape are described.
