Ammonium sulfate (AS) is the earliest production and use of nitrogen fertilizer. It is usually used as a standard nitrogen fertilizer, nitrogen content is between 20% to 30%. It is a very important fertilizer for any kind of soil that's high in pH and needs a little bit of sulfates to work against the high calcium or the high pH. The nice thing about the ammonium sulfate is that the nitrogen in it is a little bit slower releasing so it lasts throughout the growing season better than the nitrate forms of nitrogen.