A water tank is connected through a pump and a valve to an inductor container which in turn is connected through a valve to a foam holding tank which is pressurized by it being connected to an air compressor for delivering foam to an outlet for providing a foam guideline on the ground. The valves into and out of the inductor container are first closed and then the inductor container is filled with liquid foam. The valves are then opened and water under pressure is delivered to the inductor container where it is mixed with the foam and then delivered into the foam holding tank. The valves are again closed and a drain valve on the inductor container is opened to removed water from the inductor container in preparation for the next filling cycle.

Aqueous agricultural foam marker compositions for delineating treated from untreated areas comprise a foamable composition of an anionic surfactant which is an .alpha.-olefin sulfonate and/or an alkyl ether sulfate, a linear C.sub.12-16 alkanol, a foam stabilizing polymer, and one or more solvents. The foams produced from the foamable compositions have increased foam life, enhanced wind resistance, and are producable over a wide range of soft/hard water conditions.

Aqueous agricultural foam marker compositions for delineating treated from untreated areas comprise foamable compositions of an anionic surfactant which is an .beta.-olefin sulfonate, an alkyl or alkyl-ether sulfate, a long chain alkylbenzene sulfonate or a sulfosuccinate; a linear C.sub.14 or C.sub.16 alkanol or mixtures thereof; one or more solvents; and optionally a foam stabilizing polymer. The foam produced from the compositions have increased foam life, a pour point of 10.degree. C. or lower, and are producable over a wide range of soft/hard water conditions.