6 ways to prepare for tighter slurry regulations

Pressure from the government’s Clean Air Strategy to cut ammonia emissions means farms must look closely at slurry and manure management this year – if they haven’t done so already.

But doing so can be a win-win, as making better use of slurries and manures should help reduce the need for bought-in fertilisers, explains SAC consultant Neil Carter.

Cutting synthetic fertiliser use will help meet ambitious emissions targets, which include the NFU pledging to be net zero by 2040 and other supply chain initiatives to achieve net zero by 2030 or earlier.

See also: January deadline for tougher rules on slurry storage and spreading in Scotland

Mr Carter advises farmers to look at grant options now before they disappear, and get ready for when the new Slurry Investment Scheme (SIS) comes on stream later this year.

With so much pressure on farms to manage their slurry better, the scheme could be inundated with applications when it opens (date currently unknown), he warns.

Mr Carter gives some tips on how to prepare.

1. Calculate a value for your slurry

Start by using the RB209 document from AHDB and farm soil samples.

RB209 is used to assess “crop need” (see “4. Assess if you can comply with the Farming Rules for Water”). These rules are legally enforceable and not part of cross-compliance.

Nutrients are calculated as cubic metres (cu m) at a given dry matter (DM). Average dairy slurry is about 6% DM; at 2% it will be full of parlour washings and rain, while 10% DM is typical for suckler cow slurry.

Sampling slurry gives a more accurate measure, and costs about £40. Combined with a soil test, this can help you assess what the crop need is.

Nutrient availability in slurry depends on conditions at spreading, soil type and time of year. RB209 can help you work this out.

For example: a 6% DM slurry valued at December 2021 market prices would be worth the following:

• Nitrogen 2.6kg (5-45% availability) £1.40/kg
• Phosphate 1.2kg (50% availability) £1.03/kg
• Potassium 2.5kg (90% availability) £0.75/kg

A 22cu m/ha slurry application is worth £31.35 in bought-in fertiliser. By comparison, 100kg of 20:10:10 supplies £45.80 of fertiliser.

2. Check how old your slurry store is

Adaptations such as fitting covers to old slurry stores in England (pre-1991) mean Storing Silage, Slurry and Agricultural Fuel Oil (SSAFO) regulations will apply.

This could complicate the process of making such stores Clean Air Strategy-compliant because:

• Slurry stores built after 1991 should be SSAFO-compliant. As such they hold a minimum of four months storage
• Stores built in 1991 or earlier are SSAFO-exempt, providing they are not posing an environmental risk (such as leaking). However, if you are required to cover the store within the next five years to reduce ammonia emissions under the Clean Air Strategy, the work is classed as an alteration
• SSAFO regulations would then start to apply, requiring the farm to have at least four months’ slurry capacity.

Note that the SIS will only help to build stores with six months’ capacity. Some manufacturers have said they won’t attempt to cover old stores, even those built as recently as 2010.

3. Research your location to avoid SSSI planning issues

Some farmers have invested in slurry storage proactively, only to be caught out because their farm is in an Impact Risk Zone (IRZ) for ammonia near a Site of Special Scientific Interest (SSSI).

To find out if your farm is in an IRZ, go to the map at magic.gov.uk. Use the menus on the left to navigate to designations for specific areas of farmland.

Click on SSSI Impact Risk Zones to bring up lilac-coloured lines. Click on the “i” button to bring up information regulating developments at that location.

You can check whether your proposed slurry lagoon requires an ammonia emission assessment by Natural England.

4. Assess if you can comply with the Farming Rules for Water

A statement in August 2021 confirmed that organic manures can be spread only if:

• The crop need is not exceeded
• No risk of agricultural diffuse pollution occurs.

“Crop need” can be calculated by using RB209 or from analysis of soil and slurry data for your farm.

Grazing land with a P index of 3 or more has no crop need for P in slurry. This could be a problem as many large dairy units have soils at a P index of 5 or 6.

If you think you are going to break the Farming Rules for Water, you must alert the Environment Agency (EA), telling them what you are going to do to mitigate risk, including storage, removal, digestion or spreading on low-risk land such as a neighbouring arable field.

The EA has recruited more staff to try to catch people breaking the rules. Offenders face fines and potentially criminal prosecution in persistent cases.

5. Use a carbon audit to find a baseline for your farm

Little is known about the future value of carbon, but once it is sold by a farm, that carbon can no longer be used to help it reach net zero.

In December, carbon prices in Europe traded at £76/t, but some predict that carbon could head into the hundreds of pounds as industries scramble to offset emissions.

The best thing you can do right now is to run through a carbon audit with a consultant to:

• Spot inefficiencies in your system that can be fixed quickly, such as those associated with bought-in feed, grass utilisation or daily liveweight gain
• Prepare the business for the role carbon will play in future policy, such as net-zero targets and carbon trading
• Use a carbon audit package/consultant to find a baseline carbon figure for your farm. Could you become net negative in the future and sell your residual carbon to the highest bidder?

6. Prepare for the Clean Air Strategy

The Clean Air Strategy is putting more pressure on farmers – and other sectors – to cut ammonia (NH3) emissions.

By 2025 all slurry must be applied with low emission spreading equipment, effectively banning splash plates. 

By 2027 all slurry/digestate stores must be covered (this may be phased in earlier for large producers).

Mandatory design standards for livestock housing are expected.

Neil Carter was speaking at an Agrecalc webinar organised as part of SAC Consulting’s Carbon for Farming project