Soilman, farmhunter and haystack or others probably know about this stuff, but I know it is cheaper than lime, spreads easier and does a similar job. When I was younger I use to help my uncle spread this stuff (very heavy sacks) on his peanut fields, he was a big believer of it to help crops. How would it do instead of liming or is it something that can be an occasional additive to the soil in food plots?

Slag is cheaper because it has less carbonates, and thus less neutralizing capacity than lime. It would be a fine alternative to lime if it is reaonably priced, and it isn't high in heavy metals.