FWIW, I read in the Ronniger's Potato catalog an interesting tidbit... To paraphrase: the sugar in molasses is a good way to enhance the health of potatoes and the soil by feeding and multiplying the beneficial soil microbes. Put 1 cup of molasses (liquid) in 5 gallons of water. Stir occasionally and let it work for a day or two. Then apply the liquid so that it soaks to the root zone of the potatoes. You can do this 1-4 times during the growing season. It is said to help prevent scab as the beneficial microbes compete against the harmful soil fungus that causes it.
I'm sure you could water other things with it as well to help the soil?