Best source for what we do is gypsum. It's one of only two sulfur sources we can get that has built in pH neutrality being bound to calcium ions. If you have organic matter north of 5%, you could do 200 lbs/ac. If you're under 5%, I'd do 300 lbs/ac.
The other is epsom salt, but I've never seen/found an affordable way to get a fertilizer quantity. I have used epsom salt on some trees in extremely sandy spots, but that was mostly farting around.