Abstract: An improved dual metering tube systems for use in directing liquid to the row units of an agricultural implement uses metering tubes of different diameters, a pressure sensor to sense the pressure in a trunk line through which liquid is fed to the metering tubes and a controller for operating one or more valves to selectively direct liquid through only a set of small diameter tubes, only a set of large diameter tubes or both the small and large diameter tubes. Each of the small diameter tubes is paired with a respective one of the large diameter tubes and flow connected to a common outlet or nozzle associated with a respective row unit.