Guideline Index

Chapter 11. Introducing Fertilisers

11.2 What is a fertiliser?

A fertiliser is any material added to the soil or applied to a plant to improve the supply of nutrients and promote plant growth.

Any natural or manufactured material that contains at least 5% of one or more of the three primary nutrients – nitrogen (N), phosphorous (P), or potassium (K) – can be considered a fertiliser. Industrially manufactured fertilisers are sometimes referred to as “mineral” fertilisers. Fertilisers contain varying proportions of plant essential major (N, P, K, etc.) and minor (Zn, Mn, Fe, etc.) elements, as well as impurities and other non-essential elements. This definition includes both inorganic (mineral) and organic fertilisers and also soil conditioners, such as lime and gypsum (discussed in Chapter 7) , which may promote plant growth by increasing the availability of nutrients that are already in the soil or by changing the soil’s physical structure.