In an apparatus and system (710) for treating soil, an injection apparatus (712) is operable to inject soil treatment under high pressure down into the soil. A base unit (714) is operable to deliver pressurized fluid to the injection apparatus. The injection apparatus is connected to the base unit by a conduit (713) defining a fluid passageway therebetween, with the injection apparatus being positionable remote from the base unit. The base unit includes a base unit control system (792) for controlling operation of the base unit to deliver pressurized fluid to the injection apparatus, and the injection apparatus includes an injection apparatus control system (799) in communication with the base unit control system for controlling operation of the base unit from a position remote from the base unit.