Bulk Blending

Instead of distributing single-nutrient fertilizers separately or making use of factory-manufactured multi-nutrient fertilizers (complex fertilizers), the farmer may wish either to mix the fertilizers himself or to make use of the services of one of the retailers with blending units. This provides the opportunity to prepare special blends with nutrient ratios to suit the particular farmer's needs appropriate to his own soils and crops. Fertilizers which are to be mixed must be compatible both chemically and physically:

• Chemically, so that no gaseous loss will occur nor any decrease in nutrient availability or caking due to chemical reactions
• For safety reasons, special care should be taken when mixing of ammonium nitrate based fertilizers with other materials such as potassium chloride and trace elements. A risk assessment should be made to ensure that the blended products satisfy regulatory requirements with respect to composition and resistance to detonation and decomposition
• The input materials and the blended products should be handled and stored in line with Fertilizers Europe
  Guidance for the Storage, Handling and Transportation of Solid Mineral Fertilizers
• Non-conforming materials and wastes should be dealt with as given in Fertilizers Europe
  Guidance for Safe Handling and Use of Non-conforming Fertilizers and Related Materials for Producers
• Physically, the blended materials should be of similar granule size (normally 2-4 mm in Europe) and density to prevent segregation during transport and spreading.

Reference is made to Fertilizers Europe Guidance for Compatibility of Fertilizer Blending Material.