Making the most of muck and slurry is paramount, given the very high price of chemical fertilisers, so The Scottish Farmer spoke to Sarah Cowie, policy manager at NFU Scotland on upcoming changes to the slurry rules and how it may affect farmers.

In January, 2022, the Scottish Government made a number of changes to the controls for the storage of slurry and silage, as well as new requirements regarding more targeted and efficient application of slurry and liquid digestate.

The regulations acknowledges that while silage, slurry and farmyard manures are a valuable resource, they can cause emissions and risk polluting the water environment. In many cases, this is due to inadequate storage capacity, or poor structural integrity.

What are the rules for storage of slurry and how do you keep your storage compliant, plus how much capacity should you have?

Having sufficient storage capacity allows slurry to be used more efficiently and reduces the need to apply additional chemical fertilisers.

Sufficient slurry storage capacity will also contribute to Scotland’s commitment to reduce GHG emissions by ensuring slurry is applied when there is maximum uptake by crops.

The regulations consolidated, across the whole of Scotland, the differing slurry storage requirements set out in the NVZ Action Programme and SSAFO regulations. As a result, the slurry storage capacity is 22 weeks for housed cattle and 26 weeks for housed pigs.

A four-year transition period from the coming into force date has been proposed for all farmers outwith an NVZ to achieve compliance. The government rationale for this is to ensure slurry storage capacity keeps pace with the expansion of ruminant numbers on farm.

It should also be noted that the existing SSAFO regulations, which have been in place since 1991, already require at least six months storage.

Evidence has shown that leaching is greatest during the winter period and consolidating storage requirements in line with Action Programme for NVZs gives farmers better flexibility in planning the application of organic material to land.

What are the rules for spreading slurry?

From January 1, 2023, slurry will not be allowed to be applied by high trajectory raised splash plate or rain guns.

From this date, slurry should be applied by using precision equipment if applied by contractors, if applied on farms with more than 100 milking cows, or 200 beef cattle livestock units, and applied on pig units with more 800 fattening pigs or 800 cows. This is the same for liquid digestate.

For smaller farms, low trajectory splash plates will be allowed if they do not fall into any of these three categories. However, from January 1, 2027, all slurry must be applied by precision equipment.

What is an NVZ and how does it impact farmers?

A nitrate vulnerable zone (NVZ) is areas where the concentrations of nitrate in water exceed, or are likely to exceed, appropriate levels and farms in those areas must follow rules to reduce nitrate loss.

What are the rules for storage of digestate?

The current move towards alternative energy sources has resulted in a large number of anaerobic digestion plants being constructed. To minimise any risk to the water environment, the storage facilities for the liquid fraction from the AD, and run off from fibrous residue, will be consistent with those for slurry.

Where the storage is for application to land then the storage requirement should be sufficient to avoid spreading when there is no crop need, or when spreading conditions do not meet legislative requirements.

If liquid digestate stores do not currently meet the requirements within the regulations, a two-year transitional period from the regulations coming into force will apply.

What are the rules for spreading of digestate?

From January 1, 2023, liquid digestate can only be applied using precision equipment.

Anything else which farmers should be aware of?

The proposals also set an obligation for farmers to comply with the Risk Assessment for Manures and Slurries (RAMS) – a tool which helps plan applications of organic materials for good agricultural practice and reduce pollution risks.

Under these, a RAMS map must be produced which identifies no-spread zones and spreading risks. The risk assessment is only required when manures, slurries and other organic materials (sewage sludge/digestate) are likely to be applied.

It’s also important the person carrying out the application of organic fertiliser (ie, a contractor or member of staff) is provided with a copy of the RAMS map for the area to which material is being applied. Further guidance on RAMS is available on the FWS website.