DJS.
The same thought occurred to me as Sandy, how come it affected such a large area. Did he somehow spray the stuff in all directions?
This University of Maryland Extension article suggests using gypsum:
https://extension.umd.edu/hgic...
"Excess chloride can build up in the soil from swimming pool run off, irrigation water, or excess soil salts (sodium chloride). Chlorine (Cl) converts to chloride (Cl-) in the soil and is absorbed by plants in this form. Chloride toxicity is most common in irrigated, dry regions, seacoast areas, and near roads frequently treated with salt in the wintertime. Chloride levels can be reduced with the use of gypsum. Incorporate gypsum into the soil at a rate of 58 lbs. per 1000 square feet, in loam soils. Less gypsum is needed in sandy soils, more in heavy clay soils. Water thoroughly to leach toxic levels of chlorine from the soil."
I agree with Rick, I would go easy on the vinegar, if strong enough it is used as a herbicide itself. I've used it at one teaspoon per litre of water to temporarily lower soil pH but I would be hesitant to go any higher. Another option would be to ask your own local Extension office for advice.
