You can use various types of organic and inorganic fertilisers in your forestry activities. These include mineral fertilisers, such as ammonium nitrate and triple superphosphate, and organic fertilisers such as manure, sewage sludge and urea.

The most appropriate fertiliser will depend on your site and on the crop that you are growing.

What you must do

Agricultural activities

The law regards tree nurseries and Christmas tree production as agricultural activities. This means that you must comply with agricultural regulations controlling the application of fertilisers on farms which do not apply to other forestry operations.

However it is considered good practice for all forestry operations to follow these regulations.

Many fertilisers contain nitrates, which, if you apply the fertiliser incorrectly, can leach into surface waters and groundwater.

Nitrate Vulnerable Zones (NVZs) are areas that have been designated as being more susceptible to negative effects of nitrates on the water environment.

You should find out whether you are within a Nitrate Vulnerable Zone. If you are within an NVZ you will need to follow certain rules. Use the links below to find out how to access the maps and to see a summary of the requirements.

NIEA: Nitrate Vulnerable Zones (NVZ) in Northern Ireland

Scottish Government: Nitrate Vulnerable Zones (NVZ) in Scotland

Good practice

There are codes of good practice to help you protect your land, water and the environment from pollution. If you are working within an NVZ you should follow the regulators' codes of good practice.

Waste exemptions

Nature conservation

Waste management licences

Codes of good agricultural practice

Applying fertilisers

Limit the amount of fertiliser that you use by carefully planning where you need it and how you will apply it.

You should pay attention to the timing, method and rate of fertiliser application to make sure that the trees can take up the fertiliser and to avoid polluting the environment. Only use fertilisers appropriate for the type of site, soil and tree crop.

If you want to spread waste or sewage sludge on land as a fertiliser you must have an environmental permit, waste management licence or registered exemption. To find out more, see our guidance on landspreading.

Landspreading waste

Landspreading sewage sludge

See also Forestry Commission guidance on landspreading, sewage sludge and soil conservation.

Forest Research: Use of sewage sludge and composts in forestry

Forest Research: Forests and soil research

Forest Research: Nutrition of sitka spruce on upland restock sites 

Separate advice is available in Northern Ireland from the Forest Service.

Northern Ireland Forest Service

Protecting the water environment

Contact your environmental regulator and your water company or water authority if you plan to apply fertiliser by air. You will need to find out how sensitive local watercourses are.

Check the weather forecast - don't apply any fertilisers if heavy rain is due.

If you apply urea you must be careful to avoid contaminating watercourses. Urea is extremely toxic to fish, and this is increased where the surface waters are alkaline (with a pH of 8 or more). You should take extra care in such areas.

Heavy rainfall after you have applied urea could result in high ammonia concentrations in surrounding streams. This can cause problems if your water company or water authority, or a private supplier, abstracts this water for drinking.

Do not apply fertilisers if the ground is waterlogged, frozen, snow-covered or, at the other extreme, baked dry. This is when the risk of wash-off is at its greatest.

Apply fertiliser by hand in areas close to riverbanks, and avoid land that could end up under water.

In areas that drain into sensitive water bodies, consider:

  • applying fertiliser by hand or ground machine
  • phasing aerial treatments over several years
  • using slower release fertilisers.

In Scotland you must not apply organic fertilisers within 10m (or inorganic fertilisers within 2m) of any

  • river
  • burn
  • ditch
  • loch or coastal water

or spread organic fertilisers within 50m (5m for inorganic fertilisers) of any spring that supplies water for human consumption, or any borehole that is not capped to prevent the ingress of water. You must not spread any fertilisers when the ground is frozen (with the exception of farmyard manure), or on slopes unless there is an adequate buffer zone to prevent runoff from entering the water environment.

Forest Research: Forests and water

Storing and handling fertilisers

Avoid storing large quantities of fertiliser. Store only as much as you think you will use.

Store fertilisers:

  • at least 10 metres away from watercourses or field drains
  • under cover
  • away from sources of ignition
  • where there is no risk of flooding
  • where the risk of damage from vehicle movements or vandalism is low.

If you are storing waste materials such as sewage sludge for landspreading you can store up to 1250 tonnes of waste material, or 1000 tonnes in Northern Ireland, at the place where it is to be used for landspreading. You must make sure that the material is stored at least:

  • 10m from inland or coastal waters
  • 50m from a well, borehole or similar structure that is used as a water supply other than for a domestic supply
  • 250m from a well, borehole or similar structure used for domestic water supply.

You must not store sewage sludge for more than six months.

Bund your storage tanks. A bund is a secondary containment area that holds liquids if the main containers leak or break. The bund should be able to hold the contents of your tank plus an extra 10%.

Inspect your tanks and pipework regularly (at least once a year) for signs of damage.

Lock valves shut on tanks if the fertiliser could leak away when the valve is accidentally opened.

When washing spreaders after use, do not allow the water to enter a drain or waterway.

Have a pollution incident response procedure for dealing with spills. Ensure your staff are familiar with the procedure and how to implement it. Report pollution incidents as soon as they happen to the incident hotline on 0800 80 70 60.

GPP 21 Pollution incident response planning 

Forest Research: Forests and climate change guidelines

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