Abstract: A plurality of digging devices are mounted side by side on the same beam which is coupled to a clamping system of a vehicle or of a tank containing the liquid to be buried. Each device comprises, mounted on the same chassis, at least a disk for forming and opening a furrow on the ground surface. The liquid to be buried is injected into the opened furrow and then it is covered after the injection. The disk (15) has at least one convex face. The disk (15) is mounted to stand almost vertical with its axis of rotation, in an almost horizontal location which is perpendicular to the forward moving direction of the device. The clamping system is designed to exert a vertical downward force on the disk (15).