PROBLEM TO BE SOLVED: To provide a method for ozone sterilization of the nutritious liquid suppressing precipitation of minor elements in solution while maintaining a bactericidal effect, a method of an additional fertilization which replenishes the precipitated minor elements, and a nutritious liquid cultivation device using the same.SOLUTION: An ozone supply control method measures an oxidation reduction potential value of nutritious liquid and stops ozone supply when confirming shift to a state that the oxidation reduction potential value of the nutritious liquid is an approximately constant value after the oxidation reduction potential value of the nutritious liquid reaches a peak and then decreases. An additional fertilization amount control method acquires ozone supply amount by multiplying ozone concentration supplied to the nutritious liquid by the supply time thereof, acquires minor element amount precipitated from the nutritious liquid in accompany with the ozone supply on the basis of a pre-obtained correlation between the ozone supply amount and the precipitation amount of the minor elements, and replenishes the minor elements amount of which is the same as that of the precipitation of the minor elements to the nutritious liquid tank.SELECTED DRAWING: Figure 7COPYRIGHT: (C)2018,JPO&INPIT【課題】殺菌効果を維持しながら溶液中の微量元素の析出を抑制した養液のオゾン殺菌方法及び析出した微量元素を補充する追肥方法、並びにこれらの方法を用いる養液栽培装置を提供することにある。【解決手段】養液の酸化還元電位値を計測し、養液の酸化還元電位値がピークに達した後に減少に転じ、その後、前記養液の酸化還元電位値が略一定値で推移する状態に移行したことを確認した段階でオゾン供給を停止することを特徴とするオゾン供給制御方法と、養液に供給したオゾンの濃度とその供給時間との積算よりオゾン供給量を求め、そのオゾン供給量と、予め求めておいたオゾン供給量と微量元素の析出量との相関関係とに基づいて、オゾン供給に伴って前記養液から析出した微量元素量を求め、その析出量と同量の微量元素を前記養液タンクへ補充することを特徴とする追肥量制御方法である。【選択図】 図7
