Cold Water Insoluble Nitrogen 
The percentage of insoluble nitrogen fertiliser content (in urea formaldehyde or methylene urea products) which results from being placed in water at a temperature of 25°C for 15 minutes. (BS ISO 19670: 2017)
Cold Water Soluble Nitrogen
The percentage of soluble nitrogen fertiliser content (in urea formaldehyde or methylene urea products) which results from being placed in water at a temperature of 25°C for 15 minutes. (BS ISO 19670: 2017)
Complete Fertiliser
A term that is also referred to as a Complete Feed. This is a fertiliser that contains each of the three macronutrients of Nitrogen, Phosphorus and Potassium.
Complex Fertiliser
A term used to describe a fertiliser that contains two or all three of the primary plant nutrients.
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Compost Tea
A microbial liquid concentrate with a range of organisms and bases: natural soil fungi and essential bacteria, along with protozoa and beneficial nematodes, Molasses for microorganism growth, Humic Acid for fungal growth, plant nutrients and compost base. Compost tea brews should not be mixed with inorganic chemicals or fertilisers. The concentrate is added to water to create a compost tea brew, this is matured for about 12-48 hours, depending on what is required, for example, a bacterial tea through to a protozoan dominant tea, and then added to a larger quantity of water.
Compound Fertiliser
A manufactured, primarily chemically combined, fertiliser, which are probably the commonest type used on turfgrass surfaces.
According to the Fertilisers Regulations 1991 it can mean by blending as well.
It will include a minimum of two nutrients, for example, Nitrogen and Phosphorus.
Traditionally, especially prior to the later 1970s, this term also meant a complete fertiliser which supplied all three main nutrients of N P K and which could be produced from the physical mixing of fertilisers. Up until this period the supply of manufactured compound fertilisers was not as extensive as in more modern times.
Controlled Release Fertiliser
A manufactured fertiliser which has a coating material applied to reduce the rate at which the enclosed nutrient is released. The nutrients are therefore artificially controlled in their release. This term may sometimes just be referred to as just Controlled Release.
The release of nutrients is over an extended period of time, for example 3-months or greater, with an example being ICL Sierrablen. Use of this type of fertiliser may only require a single application during early spring and then a further addition of a small liquid feed during the latter part of the growing season. Some control
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Controlled Release Fertiliser (CRF)
A manufactured fertiliser which has a coating material applied to reduce the rate at which the enclosed nutrient is released. The nutrients are therefore artificially controlled in their release. This term may sometimes just be referred to as Controlled Release.
Copper
A micronutrient, which is represented by the chemical symbol Cu. Copper is involved with oxidation and reduction processes within a plant, including photosynthesis, respiration and transpiration, as well as chemical reactions involving Nitrogen. It contributes to the integrity of cell walls.
Deficiencies result in reduced carbohydrate production, a stunted growth, wilting of leaves, and often a bluish tinge on the tips of leaves. New leaves can show interveinal chlorosis, whilst this can become more widespread with necrosis in older leaves.
Crop Nitrogen Requirement
In agriculture this is the amount of nitrogen that needs to be given to a crop to achieve an optimum yield in an economically viable way. For a turf culture situation this would be the amount of nitrogen needed to maintain the desired quality surface, whilst supporting the required levels of usage.