Ammonium Sulfate is on my "do not use" list as it is extremely acidic, more so than just about any fertilizer. Our soil is already too acidic. In parts of the USA , where soil is too alkaline, it is one of the best fertilizers. Historically, nitrogen fertilizers were nitrates. Nowadays, they seldom put nitrates in fertilizer for a couple of reasons. Of course cost is number one, too expensive. But number two is they are used as explosives. A nurseryman once told me his favorite fertilizer was calcium nitrate. It turns plants green in a few days.