Materials affecting the growth of plants solely by supplying nutrients ordinarily required for growth or materials which are used to prevent or cure mineral deficiencies in plants as listed below:

Mixtures of fertilisers covered individually by different subclasses of class C05, e.g., superphosphates with ammonium nitrate, Thomas phosphate with potassium compounds, alkali or ammonium orthophosphates with ammonium nitrate, ammonium nitrate with limestone or calcium carbonate, ammonium sulfate with potassium compounds or fertilisers containing plant vitamins or hormones with fertilisers containing potassium from minerals or volcanic rocks.

Mixtures of one or more fertilisers with additives not having a specifically fertilising activity, e.g., pesticides, soil conditioners, wetting agents, nitrification inhibitors or superabsorbent polymers.

Fertilisers characterised by their form, e.g., granules, spikes or tablets.

Preparation, treatment or modification of any of the materials above: e.g., by chemical means (e.g. addition of stabilisers, preservatives), physical means (e.g., irradiation, concentration, purification, separation) or combination of both chemical and physical means, with the proviso that the resultant product is proper for classification in this subclass.

Methods of preparing fertiliser mixtures of the above subclass in general.

Fertilisers in liquid form; Special formulations prepared to obtain a liquid form of the fertiliser.

In contrast to fertilisers (C05), plant growth regulators (A01N) are those materials which alter a plant through chemical modification of plant metabolism, for example auxins.

Soil-conditioning materials or soil-stabilising materials are classified in C09K 17/00 and covers mixtures of soil-conditioning materials or soil-stabilising materials with fertilisers where the composition in question is characterised by the soil-conditioning or soil-stabilising properties.

Mixtures of soil-conditioning materials or soil-stabilising materials with fertilisers where the composition in question is characterised by the fertilising activity are classified in C05G

Whilst the subject matter of C05G deals with mixtures of fertilisers per se, A01C 3/00 deals with methods of treating manure/methods of manuring per se and A01C 21/00 deals with methods of fertilising per se.

Apparatus relevant to the subclass C05 (if no specific entry for apparatus is provided, e.g., C05B 1/10 apparatus for the manufacture of superphosphates) are to be classified in the place dealing with the process, otherwise in the place dealing with the products as such.

Additionally, individual or specific types of apparatus can be classified in the relevant area of the IPC, e.g., F26B 17/00.

An ingredient in a mixture of fertilisers, or a single fertiliser which contains more that one of the chemical elements on which the subdivision into subclasses is based, is classified only in the first of the appropriate subclasses. Thus, a nitrophosphate or an ammoniated superphosphate is classified in C05B but not in C05C, magnesium phosphate is classified in C05B but not in C05D, and calcium cyanamide in C05C but not in C05D.

Information relative to the form in which the fertilizer is presented, e.g. granulation, coating, etc. is always given in addition to the chemical composition of the fertilizers.

General statements in relation to a " fertiliser being formulated as liquid, powder, granulate or any other suitable form" are not given per se a class in this group. Not all possible liquid fertilisers are classified in this subclass, only when the fertiliser is liquid and is an important feature of the invention.

Any ingredient in a mixture, which is considered to present information of interest for search, is also classified using a combination of classification symbols. If a document concerns embodiments comprising mixtures whose elements are covered individually by different subclasses, groups or subgroups, the document is classified with a Combination-set.

The following rules apply:

Example: a fertilizer containing a mixture of superphosphate (C05B 1/02), ammonium nitrate (C05C 1/00) and potassium chloride (C05D 1/02) will be given the Combination-set C05B 1/02, C05C 1/00, C05D 1/02.

Example: a fertilizer containing a mixture of either superphosphate (C05B 1/02) or ammonium nitrate (C05C 1/00) with potassium chloride (C05D 1/02) will be given the Combination-set C05B 1/02, C05D 1/02 and C05C 1/00, C05D 1/02.

This group is mainly used as additional information or for documents difficult to classify anywhere else in the previous groups of this classification as it would be the case for unspecific mixtures of organic and inorganic materials .

In the case of mixtures with well defined components, combination classes giving specific information about these components will be used instead.

Fertilisers mixed with substances not encompassed under the finer classification given below. Some examples of substances classified in this group are : colorants and pigments, corrosion inhibitors, odours, preservatives, magnetic materials etc.

Whether a fertiliser is characterised by the materials it is prepared from and the form which it presents a class pertinent to both aspects should be given.

Mixtures of fertilisers with other compounds mainly to improve the physical structure or water retention capacity of soils for agricultural purposes. These compounds are e.g. water retaining polymers, sand or clay materials.