SOA is a valuable fertiliser as a straight product or in blends.
Sulphur in SOA is sulphate sulphur which is the form taken up directly by plants. Sulphate sulphur is readily soluble in water and goes straight into solution when applied to the soil (providing there is moisture).
SOA releases nitrogen to the soil directly as ammonium NH4+, which is converted by bacteria to nitrate nitrogen. This process is favoured by conditions conducive to microbial activity, such as warm temperatures, moisture and organic matter. The rate of this reaction depends on those conditions and complete nitrification of applied ammonium can vary from a few days to several weeks.