An elongated boom having a plurality of sprinkler heads mounted thereon with the boom being constructed of a plurality of articulately connected sections supported by electrically driven wheeled assemblies for propelling the boom in a circular path about a central standpipe. The boom is in the form of a truss construction, the articulate connections between the sections of the pipe are disposed interiorly of the flow path and the sections of the boom are retained in alignment in either direction of movement. An end gun is provided and cam operated to irrigate the normally missed corners of a square area and the lugged wheels on the supporting assemblies are timed so that the lugs track thereby providing less disturbance of the ground surface.
