Sulphate of Potash or Potassium Sulphate

(SOP) 0-0-41-17

1. FEATURES

SOP provides both Potassium and Sulphur (K₂SO₄).

Potassium stimulates the growth of strong stems and gives the plant some disease resistance by promoting thickness of the outer cell walls. Adequate potassium can reduce moisture loss from growing plants, thereby giving some drought resistance. Potassium improves colour, flavour and storing quality of fruit and vegetables.

Potassium is present in all soils in reasonable quantities. In fact potassium is the seventh most abundant element in the Earth’s crust. At least 88% of the soil potassium is in the form of silicates, and so unavailable. The available forms leach readily, particularly in the higher rainfall areas & lighter soils. There are four commonly used Potassium fertilisers:

2. TYPICAL ANALYSIS

3. PHYSICAL PROPERTIES

4. MANUFACTURE

Potassium Sulphate is either mined and processed to clean away unwanted salts;

OR

Muriate of Potash is reacted with Sulphuric Acid.

2KCl + H₂SO₄ = K₂SO₄ + 2HCl

5. USES

Potassium sulphate can be a more expensive source of potassium than MOP and so its uses are often restricted to five main areas.

1. Where soil or irrigation water salt levels are high and MOP is undesirable
2. Where chloride sensitive crops are being grown, e.g. berries, vines
3. Where quality or cadmium uptake may be affected by excess chloride, e.g.      potatoes and leafy vegetables.
4. For organic grown crops (mined SOP only).
5. Where high chloride levels occur in irrigation water.

Potassium Sulphate blends readily with all other fertilisers providing particle sizings are matched.

6. STORAGE AND HANDLING

Potassium sulphate can be stored in bulk bags. It does not bond in the heap. Potassium sulphate is slightly hygroscopic and is neutral in reaction. All potassium fertilisers are corrosive and care should be taken when the fertiliser is in contact with metal. After application wash all machinery out with water.