According to (EC) Regulation no. 2003/2003 of the European Parliament and the Council of 13 October 2003, the definition of a fertilizer is a “substance whose main function is to deliver nutrients to plants”. And an inorganic fertilizer is a “fertilizer that contains declared nutrients in the form of minerals obtained by extraction or physical and/or chemical industrial processes”. According to the above-mentioned Regulation, inorganic fertilisers are classified into several basic groups:
- simple fertilisers (nitrogen fertilizers, phosphorus fertilizers, potassium fertilizers);
- multi-component fertilizers being a mixture of nitrogen, phosphorus, and potassium (NPK, NP, NK, PK);
- liquid mineral fertilizers, without solid particles;
- mineral fertilizers containing secondary nutrients(calcium, magnesium, sodium, sulfur);
- mineral fertilizers containing microelements (boron, cobalt, copper, iron, manganese, molybdenum, zinc).