Fertilisers are all compounds and substances, regardless of physical form, that contain plant nutrients and are added to soil or plants to improve growth, increase crops and improve crop quality or soil fertility.

Plant nutrients are divided into:

  • primary nutrients or macro-nutrients: nitrogen (N), phosphorus (P) and potassium (K),
  • secondary nutrients: calcium (Ca), magnesium (Mg), sodium (Na), sulphur (S) and
  • micro-nutrients: boron (B), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn), these are  important for the growth of plants in quantities that are small compared to the quantities of primary and secondary nutrients.

Fertilisers are further divided into:

  • mineral fertilisers that contain exclusively mineral components and are obtained with an industrial process and
  • organo-mineral fertilisers which besides mineral components also contain organic substances of animal or plant origin and are obtained with extraction or with physical or chemical industrial processes.

Analyses of fertilisers are performed with the purpose of determining the compliance of the content of primary, secondary nutrients and micro-nutrients with the declared values. We also determine physical properties of fertilisers and the content of undesirable substances, such as heavy metals. We use methods of analysis and testing that are prescribed in Regulation 2003/2003/EC, Annex IV and also standard (ISO, EN) methods.

Analysis Methods

Analyses of Fertilisers


In fertiliser analysis, we ensure the quality of services by using modern measuring equipment that we regularly check and calibrate ourselves or with the help of authorised institutions. We use reference materials and calibration standards with guaranteed traceability, internal reference materials, control charts and other tools that enable constant on-line quality control of the obtained results.


Agricultural Institute of Slovenia is authorised  byThe Ministry of Agriculture, Forestry and Food of the Republic of Slovenia (Official Gazette of the Republic of Slovenia, No. 103/2006) to perform chemical analyses for the requirements of inspection in the mineral fertilisers trade.

Contact person

mag. Vida Žnidaršič Pongrac, univ. dipl. kem., tel.:+ 386 1 280 51 62