Abstract: Disclosed is the use of oxygen delivery vehicles, including peroxides of calcium, potassium and magnesium, to treat plant media having a negative reduction oxidation potential. The peroxides are preferably intercalated with phosphate ion which prolongs the period of time during which oxygen is released. The peroxides may be mixed with macronutrients, micronutrients or other beneficial additives or amendments, to provide fertilizers or applied direct to the media. Effective amounts of metals are used as bioactive agents for suppressing or enhancing the activity of microorganisms in the soil, depending on whether such microorganisms are detrimental or beneficial to plants. The formulations are useful in treating anaerobic associated disease states such as black layer in turf. The formulations are also useful in controlling post harvest potato soft rot and other microbial infection and disease states in plants.