The most common use is as a soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions. In fertilizer the purpose of the sulfate is to reduce the soil pH. It is used largely as an artificial fertilizer for alkaline soils. In the soil the sulfate ion is released and forms bisulfate, lowering the pH balance of the soil (as do other sulfate compounds such as aluminium sulfate), while contributing essential nitrogen for plant growth. It is also used as an agricultural spray adjuvant for water soluble insecticides, herbicides, and fungicides. There it functions to bind iron and calcium cations that are present in both well water and plant cells. It is particularly effective as an adjuvant for 2,4-D (amine), glyphosate, and glufosinate herbicides. It is also used in the preparation of other ammonium salts. content of Nitrogen: 21%min Moisture: 0.2% Free Acid(As H2SO4) 0.03%max Content of Iron(Fe) 0.007%max Content of Arsenic(As): 0.00005%max Content of Heavy Metal(by pb) 0.005%max Content of Water insoluble substance 0.01%max Please don't hesitate to inform us if anything i can help.