Variable volume flow injection nozzle

A method of delivering invasive species toxin to a body of water, the method comprising:

• using a low air entrainment mixer to mix a wettable solid with water without substantial entrainment of air to produce a toxin;
• delivering the toxin mixed by the low air entrainment mixture to a tank of a boat including a propulsion system for moving the boat along a surface of a body of water in a propulsion direction as directed by a steering wheel;
• moving the boat along the surface of the body of water in the propulsion direction to a location of an invasive species;
• and
• pumping the toxin from the tank to a nozzle extending laterally across the propulsion direction at a predetermined delivery rate, the nozzle supported by nozzle supports extending downward from the boat to hold the nozzle beneath the surface of the body of water at a predetermined distance;
• wherein the nozzle provides at least one laterally extending opening presenting a variable fluid flow resistance as a function of lateral distance to promote uniform flow rate as a function of lateral distance.