An assembly as used with a drop tube of a moving irrigation system which allows the operator to convert from conventional spray mode operation to furrow bubbler operation. The assembly includes a pressure regulator for regulating the pressure of water to a relatively low value and having an upper end adapted to be connected in water communicating relation to the drop tube and a spray head connected at its upper end in water communicating relation to the lower end of the pressure regulator. The spray head includes a nozzle for directing a water stream downwardly in a direction to be normally interrupted by a removable splash plate into a spray pattern. A tubular structure is connected at its upper end portion with the spray head in a position to receive all of the water stream directed from the nozzle so as to transmit the same downwardly to the lower end thereof. A bubbler device is carried by the lower end of the tubular structure in a position to receive the water in the lower end thereof and deliver the same at extremely low pressure at a position near ground level.