The Collaborative International Dictionary of English v.0.48:

Agricultural \Ag`ri*cul"tur*al\, a.
   Of or pertaining to agriculture; connected with, or engaged
   in, tillage; as, the agricultural class; agricultural
   implements, wages, etc. -- Ag`ri*cul"tur*al*ly, adv.
   [1913 Webster]

   Agricultural ant (Zool.), a species of ant which gathers
      and stores seeds of grasses, for food. The remarkable
      species (Myrmica barbata) found in Texas clears circular
      areas and carefully cultivates its favorite grain, known
      as ant rice.
      [1913 Webster]