A distribution tube assembly for an irrigation system having a main supply line for conveying fluid therein includes a first end, a second end and an internal surface defining at least two fluid passageways, at least one of the fluid passageways being in fluid communication with the main supply line. The other fluid passageway may be in fluid communication with an alternate supply line. Adaptors and regulators may be attached to the distribution tube assembly. The distribution tube assembly permits irrigation to be performed by multiple fluid streams, allows for the incorporation of chemicals within the distribution tube assembly, and provides for selectable flow control.