Most sulphur-containing fertilizer materials generally can be divided into four groups: 1) fertilizers containing sulphate, 2) fertilizers containing elemental sulphur, 3) fertilizers containing a combination of sulphate and elemental sulphur, and 4) liquid sulphur fertilizers. Sulphate-containing fertilizers provide most of the fertilizer S applied to soils. These materials have the advantages of supplying S primarily as a component of multi-nutrient fertilizers in a form, SO4-2, that is immediately available for plant uptake. The most readily available and popular sources are ammonium sulphate (AS), single superphosphate (SSP), potassium sulphate, and potassium and magnesium sulphate. Click here to read more. Elemental S based fertilizers are the most concentrated S carrier. Modern technologies increased their use in direct applications or as additives to N-P-K fertilizers