Abstract: A mobile irrigation system of the type including an elongated horizontal water conduit assembly having support structure spaced therealong for support from and movement over the ground is provided. One end of the water conduit assembly may be communicated with a source of water under low pressure and a plurality of discharge pipes are supported from the assembly at points spaced therealong and open upwardly and outwardly from the interior of the conduit assembly. A plurality of motor driven generally horizontal and centrally apertured discs are journaled from the assembly and the discharge pipes project upwardly through the central apertures in the discs.