A soil working apparatus comprises a first structure moveable above a soil surface along a travel direction and a plurality of second structures connected to the first structure in a spaced apart manner along a direction substantially perpendicular to the travel direction. Each second structure pivotally supports at least one knife selectively pivotable about a substantially vertical axis between a plurality of pivoted positions. A locking mechanism locks the knife(s) of each of the second structures in a selected one of the pivoted positions. The selected pivoted position for the knife(s) of each of the support structures is independent of the selected pivoted position for the knife(s) of other support structures.