Nutrient Uptake and Yield Response to Polysulphate By Different Crops.

Polysulphate is a new multi-nutrient fertilizer, available in its natural state, and mined in the UK.  It has four nutrients: sulphur (48% SO₃ as sulphate), potassium (14% K₂O as sulphate of potassium) magnesium (6% MgO as magnesium sulphate) and calcium (17% CaO as calcium sulphate). It is a soluble material therefore its nutrients are readily available for plant uptake.

Polysulphate comes from the polyhalite layer of rock, over 1000m below the North Sea off the North Yorkshire coast in the UK.

Polysulphate is the trade mark of the mineral 'Polyhalite', which is one of a number of evaporate minerals containing potassium. Polyhalite (dehydrate) is a single crystal complex with 2 molecules of water of crystallization. It is not a mixture of salts. The chemical formula is K₂Ca₂Mg(SO₄)₄•2(H₂O).

Independent trials have shown Polysulphate to be a good source of S, K, Mg and Ca.  Polysulphate trials have focused on establishing that its nutrients are readily available to the plant. Crops were grown and given standard sources of pure potassium and magnesium sulphates, or Polysulphate. Uptake of the Polysulphate nutrients by the plants was found to be as good as the standard equivalent fertilizers already used in the field.  These trials have been repeated many times over the last ten years, both in pots and in the field. Polysulphate has performed equally well or better than the best standard alternatives.

Field trials in the UK investigated the response of cabbage and grasses to Polysulphate fertilizer. Polysulphate has been also tested in field trials for some major arable crops in France. Field trials on potatoes were also performed in Germany to test the agronomic efficiency of Polysulphate.

In India, experiments were done for mustard, cabbage and cauliflower. Pot experiments were performed in Brazil for measuring nutrient uptake and yield response of rice.