Agricultural Use of Ammonium Sulfate

Ammounium sulfate is used primarily where there is a need for supplemental N and S to meet the nutritional requirement of growing plants .Since it contains only 21% N ,there are other fertilizer sources that are more concentrated and economical to handle and transport .However ,it provides an excellent source of S which has numerous essential functions in plants ,including protein synthesis .

Because the N fraction is present in the ammonium form ,ammonium sulfate is frequently used in flooded soils for rice production ,where nitrate -based fertilizers are a poor choice due to denitrification losses .

A solution containing dissolved ammonium sulfate is often added to post-emergence herbicide sprays to improve their effectiveness at wed control .This practice of increasing herbicide efficacy with ammonium sulfate is particularly effective when the water supply contains significant concentrations of calcium ,magnesium or sodium .A high-purity grade of ammonium sulfate is often used for this purpose to avoid plugging spray nozzles .

Management Practices

After additions to soil ,the ammounium sulfate rapidly dissolves into its ammonium and sulfate components .If it remains on the soil surface ,the ammonium may be susceotible to gaseous loss in alkaline conditions .In these situations ,incorporation of the material into the soil as soon as possible …or application before an irrigation event or a predicted rainfall …is advisable .

Most plants are able to utilize both ammounium and nitrate forms of N for growth .In warm soils ,microbes will rapidly begin to convert ammonium to nitrate in the process of nitrification .Durning this microbial reaction ,acidity is released ,which will ultimately decrease soil PH after repeated use .Ammonium sulfate has an acidifying effect on soil due to the nitrifaction process ,not from the presense of sulfate ,which has a begligible effect on PH .The acid-producing potential of ammonium sulfate is greater than the same N application from ammonium nitrate ,for example ,since all the N in ammonium sulfate will be converted to nitrate ,while only half of the N from ammonium nitrate will be converted to nitrate .