Abstract: A mixing body for diverting a portion of a liquid, e.g., water flow, into a cartridge of fertilizers, fungicides, hormones, pesticides or the like to form effluent. The effluent is reintroduced to the water flow and goes to a downstream sprinkler or application system. The cartridge, which may contain liquid concentrate, is inserted into the mixing body, which has inlet and outlet one way valves that puncture a sealing layer of the cartridge. The diluted effluent exits through the outlet one way valve and is thus delivered to the irrigation system. The amount of effluent can be regulated by a needle valve that controls the amount of effluent exiting the manifold. The mixing body has a locking system to securely hold the cartridge in place. There is also a plate to protect a user from the sharp inlet and outlet valves when the cartridge is removed.