Abstract: The present invention provides a system and method for the disinfection of irrigation water. Irrigation water is exposed to ozone, which disinfects and flocculates the water for improved removal of bacterial contamination. One or more ozone generators produce ozone gas that is injected into the flow of irrigation water at one or more points in an irrigation water treatment system. The ozone may be hyper concentrated, and the mixing of ozone and water may be optimized so that the maximum amount of water is exposed to a concentration of ozone that is high enough to disinfect the water over the period of contact. Ozonated water is then delivered to farm fields. No harmful residues remain in the water or soil after treatment.