Lack of compatibility may only result in the formation of a jell, precipitate, or sludge that plugs up screens and nozzles. But extreme incompatibility may produce a settling out of material that can harden like concrete in the bottom of the tank and in hoses, pumps, and other internal parts of the sprayer. The result may be total loss of the pesticide and use of the sprayer.
Incompatibility can also reduce effectiveness or cause crop injury.
Herbicides may be combined with liquid fertilizers to minimize trips over the field. However, information is scarce concerning the compatibility of herbicides with specific fertilizer solutions. Herbicide-fertilizer solution combinations may form a gel or precipitate that settles to the bottom of the sprayer tank or that will not flow through the sprayer equipment. Tank-mixing several pesticides, although convenient, may create other problems. To prevent the main water tank or liquid-fertilizer measuring tank from becoming contaminated, commercial applicators may want to mix the herbicides and other ingredients in a separate holding tank.