a mobile irrigator with a ribbon of plastic wound on a drum which is frictionally driven by wheels engaged with the ribbon , the wheels being adapted to slide on the plastic to compensate for varying diameters of the drum resulting from more or less windings of the ribbon , the drive for the drum being designed to hold the ribbon taught for passing through guides which shape the ribbon from flat to tube and vice versa . a control is provided for the pump to prevent loss of prime by limited feeding of air into the pump . a supply source of water has an electronic monitoring receiver operating a supply pump discharging into the tube to provide sufficient pressure and attendant fluid level to hold the prime in the irrigator or discharge pump . a pressure sensitive sending command unit is provided at the inlet of the irrigator pump for actuating the supply pump at the water source .