These products are no more than Manganese sulphate dissolved in water and typically contain 18 -19 % Mn w/v. This is approaching the maximum solubility of MnSO4, so they cannot contain any stability agents or adjuvants as there is no ‘room’ left in the formulation. They are unstable at low temperatures.

 

Theoretically, they should be applied at rates of application pro-rata to Manganese sulphate powder of around 7 - 8 litres per hectare at which they are not cost effective.

 

Recently, liquids based on Manganese nitrate have been introduced with theoretical maximum concentrations of about 24% w/v Mn. These products do exhibit better compatibility than sulphate based liquids and their nitrogen content causes additional cosmetic greening of the crop. However, the same arguments in terms of uptake apply if these products do not have adequate adjuvant systems added to them. They also do not contain valuable sulphur.

 

Simple inorganic liquids - Pros and Cons

  • Not formulated: Sulphates 18 - 19.5% Mn Nitrates 20 - 24 % Mn

  • Poor storage stability

  • Recommended application rates too low

  • Compatibility problems

  • Good mixing properties

  • No improvement in uptake efficiency