Agricultural Odours or Smells

Why Spread on Farmland?

Various types of waste and by-products are valuable fertilisers, and spreading them on farmland helps support healthy crop and grass growth.  The alternative would be dispose of the material to landfill sites, which would be wasteful and difficult to manage safely for the environment.  Using these natural materials reduces the need for chemical fertilisers, which require a lot of energy to produce. Producing less energy also means generating less carbon dioxide — a greenhouse gas that contributes to global warming.

Natural fertilisers often have a noticeable smell. Since many of our communities are close to farmland, it's normal to notice these odours occasionally. What can be spread on Farmland?

Traditional fertilisers include:

• Manure - Collected from farmyards and cattle sheds, often mixed with straw used for bedding during the winter. It is stored until conditions are suitable for spreading. Because it is fairly solid, manure is usually spread across fields using a tractor-mounted muck spreader.
• Slurry - A liquid form of manure that is stored in tanks before being spread. It is either injected into the soil or released close to the ground from tanker trailers, helping nutrients reach the soil efficiently.
• Hen pen (poultry litter) - Bedding material from chicken sheds that contains droppings. It is rich in nitrogen and acts as a strong fertiliser. Hen pen may have a noticeable ammonia smell and is sometimes stored in fields before being spread, usually in a similar way to solid manure.

Recent developments include:

• Sludge cake - Dried, treated solid material from the sewage system. It is nutrient-rich and looks similar to peat or dry flakes. Sludge cake can have a strong odour and is often spread on fields with lime to help incorporate it into the soil.; and
• PAS110 Biofertiliser - Produced through the anaerobic digestion of organic waste, including food waste. This material meets strict British standards to ensure safety and quality. PAS110 can be liquid or solid and may have a strong odour when spread on land.

When does spreading take place?

Farmers and contractors spread fertilisers when conditions are suitable. Before spreading, they need to consider:

• Rain: Fertilisers should not be spread before heavy rain, as nutrients can be washed into rivers and streams, causing environmental harm.
• Wind direction: Spreading should be avoided when the wind could carry odours toward nearby homes.
• Temperature: Warm weather can make smells stronger. At the same time, residents may have windows open, which can increase the impact of odours inside homes. Frost or snow can also prevent nutrients from reaching the soil effectively.
• Previous applications: There are limits on how much fertiliser land can safely absorb, so what has already been spread and when must be considered.
• Ground conditions: The soil must be firm enough to support tractors, trailers, and machinery. Wet or soft ground can make spreading unsafe or ineffective.

Spreading typically happens in late winter, before summer planting, and in late summer or early autumn, after harvest. It can also take place at other times of the year when weather and soil conditions are suitable.

Standards Expected

Guidance on spreading and reducing odours is available in 2004 publication, 'Prevention of Environmental Pollution From Agricultural Activity (opens new window)'. Some materials also have mandatory or recommended limits on how much material can be applied to land.

To minimise odour problems, Environmental Health expects:

• avoid surface spreading on pasture (grassland) near homes
• plough surface-applied material into the soil within 48 hours.

However, there may be valid reasons why it is is not always possible to follow these measures completely, and some odour may still occur.

Regulatory Controls

There are no specific regulatory controls on the spreading of:

• manure; and
• PAS110 Bio fertiliser. This is because it is classed as a product, not a waste, subject to specific criteria (opens new window).

SEPA - Scottish Environment Protection Agency (opens new window) licenses:

• the storage on land of sewage sludge cake, but not its subsequent spreading; and
• the injection of slurry, depending on the volumes concerned and the circumstances

Please note that farmers do not need to notify or obtain permission from the local authority before spreading. As a result, the Council usually does not when or where spreading will take place.

What to do when there is a problem

Some level of smell is unavoidable when agricultural materials are spread on farmland. Being able to notice these odours does not necessarily mean the farmer or contractor has done anything wrong.

• However, if you believe that: The spreading has been carried out in an unreasonable way, and
• The smell is unusually strong, persistent, or unpleasant,

you should first try to speak directly with the farmer or landowner to raise your concerns.

If this does not resolve the issue, you can contact Environmental Health. Please provide as much information as possible, such as:

• What the smell is like and when it occurs, and
• Where you think it is coming from (if known).

Please note that Environmental Health does not routinely investigate agricultural odour complaints. Investigations are only carried out when resources allow and where the problem is serious or persistent. We will liaise with the Scottish Environment Protection Agency (SEPA) when appropriate.

If there is clear evidence that best practice has not been followed and the odour is causing an unreasonable nuisance, Environmental Health may take formal action under Statutory Nuisance legislation.  Formal action is generally only taken when informal steps have not worked or when there have been repeated issues. It is important to note that formal action will not remove the odour immediately.