Fertilisers that can be applied in a liquid form are either organic (e.g. urea, seaweed) or inorganic (e.g. sulphate of ammonia, potassium chloride).

The major advantages of applying fertiliser in a liquid form are that :

• nutrients are readily available to the plant

• a high percentage of the nutrient is delivered to the plant

• it is relatively cheap

• it is easy to spread.

Some disadvantages include:

• an increased risk of leaf burn, so liquid fertilisers must be watered in well

• increased susceptibility to leaching and volatization.

Fertilisers supplied as granules account for the majority of fertilisers used in the turf industry.

The advantages of granular fertilisers include:

• ease of handling

• application equipment is readily available.

Some disadvantages are:

• granular fertilisers do not act as quickly as fertilisers in soluble form

• differing granule mass may result in some granules being thrown further than others by a rotary spreader, resulting in patchy growth

• the dust created during application.

Slow release fertilisers can be divided into three main categories:

• natural organics

• synthetic organics

• coated products.

Natural organics include fertilisers such as manures, blood and bone and bio solids. The nitrogen in these fertilisers is not readily available to the plant and needs to be broken down by soil micro-organisms. The activity of these soil microbes will depend on factors including soil temperature, pH and moisture.

Natural organic fertilisers:

• increase the soil's ability to retain moisture and nutrients

• have low leaf burn potential

• slowly release nutrients over time so that the turf manager does not need to monitor them.

Synthetic organics use formaldehyde and methylene ureas that are broken down by soil microbes to slowly release nitrogen.Examples of these fertilisers include UF.38, IBDU and coron.

Coated products include fertilisers coated with sulphur or polymers that gradually break down in the soil to release nutrients.