Farmers warned to check fertiliser and by-product ingredients

Farmers are being warned to scrutinise paperwork, supply chains and ingredients carefully before using fertiliser and by-products after it was revealed farmers in the north of England were allegedly sold an unlicensed product without their knowledge.

Farmers Weekly spoke to a livestock producer who said he had used a product, believed to have been ammonium sulphate, prior to taking first-cut silage, and herd fertility had plunged from 26% to 6% over three consecutive PD sessions once the silage was fed.

See also: Rule reminder – how to store fertiliser safely

The product in question was actually more expensive than the fertiliser normally used and was chosen on the basis it bound to the soil better than conventional forms of fertiliser, and didn’t leach in the same way, but the farmer admits this was difficult to quantify.

The farmer, who wished to remain anonymous, said his herd health was not as badly affected as it could have been as his farm is on acidic spring water which countered the alkaline silage.

Herd health is now back to normal since moving to a different silage that wasn’t treated with the fertiliser in question.

The incidents were first reported in The Scottish Farmer last month, with one milk producer claiming he was forced to shut down his dairy farm after the same liquid fertiliser was found to be contaminated with traces of petrochemicals, anti-cancer drugs and other harmful substances.

The farmer claimed that after spreading the product on grassland, milk yield dropped from 8,000 litres to 5,000 litres and cows were seriously ill, with one animal recording a rumen pH of 8 instead of a healthy 6.2-7.

Independent grassland specialist George Fisher said it was very tempting this season to buy cheaper products to save money, given current fertiliser costs.

However, he warned this could be a massive false economy, adding: “If you are spending £15,000 on fertiliser and trying to save £2,000-£3,000 by buying by-products, it doesn’t stack up, especially if that farm is spending £250,000 on feed every year.

“Fertiliser isn’t the big cost you should be looking at to reduce costs.”

Below, Dr Fisher gives advice to farmers on how to ensure a product is safe to use and meets the necessary legislative requirements.

1. Is it accredited?

It is the farmer’s responsibility to ensure the fertiliser used is properly accredited and safe.

Farmers can check this by making sure the product is approved by the Agricultural Industries Confederation (AIC) Fertiliser Industry Assurance Scheme (FIAS). This is an independent quality and traceability audit and provides an assurance system to ensure that the security, safety and traceability of fertilisers meet the requirements defined by legislators and industry (see “UK fertiliser regulation” below).

AIC recommends that all crop nutrient products should be purchased as “fertiliser”, either in solid or liquid form, conforming to the 1991 GB fertiliser or 2003 regulations, and from AIC members covered by FIAS. 

There are legal limits on the use of heavy metals within compound fertilisers containing nitrogen, phosphorus, potassium and sulphur (NPKS), and these are also checked by FIAS. Liquid fertiliser is also covered by FIAS.

2. Check the ingredients carefully

By-products such as straight ammonium sulphate and organic wastes are not necessarily covered by FIAS because they are variable and often come from different manufacturing processes.

But you can still ask for a full breakdown of ingredients. This should include:

• Heavy metals
• NPKS
• Trace elements
• Non-organic components
• Organic components.

If the supplier of the product cannot give you a complete breakdown, don’t use it.

3. Beware of the ways some waste products interact with soil biology

Paper waste and woodchip are high in carbon, and soil microbes react by sucking in available nitrogen so they can break down the material, diverting it away from the plant for growth.

Because of this interaction it is very difficult to give accurate nitrogen recommendations for soils that have been treated with high-carbon products.

If you are considering buying by-products that are high in carbon, get a carbon soil analysis done to understand your starting point. You may have some soils that need carbon and others that don’t.  

4. Check with your assurance scheme or supplier

Different schemes or customers will have different stipulations on the use of by-products and will require a complete analysis (see “Red Tractor requirements when using fertilisers” below).

For example, Linking Environment and Farming (Leaf) requires a full analysis of products and justification for application as part of a nutrient management plan within its Leaf Marque standards and this rigorous approach is essential.