Inorganic fertilisers (mineral fertilisers), according to the classification established in the Polish European Standard EN 13535 (2003), are “Fertilisers – added to soil specifically to feed crops – in which the declared nutrients are in the form of inorganic salts obtained by extraction and/or by physical and/or chemical industrial processes.” The preferred terminology is “inorganic fertiliser,” whereby nitrate, urea, and its derivatives and bone superphosphate may conventionally be classified as inorganic fertilisers.
Inorganic fertilisers (mineral fertilisers) do not include liming materials in the European Union. The definition of a liming agent according to the European standard PN-EN 12944-3 (2002) established in Poland is as follows: “liming agent (fertilising lime) – an inorganic substance containing calcium or magnesium (one or both elements), mainly in the form of an oxide, hydroxide, carbonate or silicate intended primarily to maintain or raise the pH level of soil and water and to improve plant nutrition, as well as to change the physical properties of the soil.”
The figure (below) shows a classification scheme for fertilisers and liming materials in the European Union based on standard EN 13535 – Fertilisers and liming materials – Classification (2003).
Classification scheme for fertilisers and liming materials (EN 13535, 2003)
The European Union legislative area covers inorganic (mineral) fertilisers in the following main groups:
A. Simple fertilisers – nitrogen, phosphorus, potassium-containing only one essential fertilising component.
B. Multicomponent fertilisers contain more than one essential fertilising element; NPK, NP, NK, and PK fertiliser.
C. Liquid fertilisers – simple liquid fertilisers and multi-nutrient fertilisers.
D. Fertilisers containing secondary fertilising ingredients such as calcium, magnesium, sodium, and sulfur.
E. Micronutrient fertilisers containing: boron, cobalt, copper, iron, manganese, molybdenum, zinc.
F. Chelating compounds.
To put in order the terms currently used in Poland in the field of fertilisers, below there is given an elaboration of some definitions included in the European standard established in Poland in 2002 PN-EN 12944-1 “Fertilisers and liming materials – Terminology. Part 1: General terms” and referred to in Regulation (EC) No 2003/2003 of the European Parliament and the Council of 13.10.2003.
Primary nutrient – only the elements nitrogen, phosphorus, and potassium.
Secondary nutrient – the elements calcium, magnesium, sodium, and sulphur.
Micronutrient (trace element) – elements such as boron, zinc, cobalt, manganese, copper, molybdenum, and iron.
Simple fertiliser – a general qualification referring to a nitrogen, phosphorus, or potassium fertiliser having a declared content of only one primary nutrient.
Multicomponent fertiliser – a fertiliser obtained by chemical reaction or by blending or by both processes, has a declared content of at least two primary nutrients. Fertilisers having a declared content of two primary nutrients are known as bicomponent fertilisers, while fertilisers with a declared nitrogen, phosphorus, and potassium content are known as NPK multicomponent fertilisers.
Complex fertiliser – a fertiliser obtained as a result of a chemical reaction, having a declared content in the form of a chemical compound of at least two of the three essential nutrients.
Blended fertiliser – a fertiliser obtained by dry mixing of several fertilising substances rather than by chemical reaction.
Liquid fertiliser – a term referring to fertilisers in solution or suspension form and to liquid ammonia.
Fertiliser solution – a liquid fertiliser containing no solid particles.
Suspension fertiliser – a two-phase fertiliser in which the solid particles are held in suspension in the aqueous phase.
Fertiliser nutrient solubility – the amount of a given nutrient extracted under specified conditions by a specific reagent, expressed to the weight of the fertiliser.
Declaration – the fixed content of a nutrient, including its form and solubility guaranteed within specified tolerances.
Declared content – the content of an element (or oxide) which, following the Act, may be stated on the label, printed on the package, or in an accompanying document.
Conformity assessment – the assessment by official inspection bodies of the conformity of the manufacturer’s quality declaration with the actual state of affairs and with the requirements for EC fertiliser.
The following is also an elaboration on the term liming material (EN 12944-3, 2001)
A liming material (fertiliser lime) is an inorganic substance containing calcium or magnesium, one or both elements, mainly in the form of oxide, hydroxide, carbonate, or silicate, intended primarily to maintain or increase the pH level of soil and water and to improve plant nutrition, as well as to change the physical properties of the soil.