Advice drawn up by the National Counter Terrorism Security Office, the Agricultural Industries Confederation, the farming unions and Defra has been updated and re-issued in a new leaflet, Don't be the weakest link in the chain, aimed at the farming industry.
New recommendations include buying fertiliser from suppliers approved by the Fertiliser Industry Assurance Scheme (FIAS) and to retain and file all of the related fertiliser delivery notes.
FIAS is a voluntary scheme set up three years ago to manage security and traceability in the UK fertiliser supply chain but it does not extend to farms and holdings.
NFU inputs adviser Hannah Moule said it was important farmers and growers follow best practice not just because fertiliser could be misused in the wrong hands but also because failure to do so could lead to more regulation in future.
"The NFU supports any improvement that can be made in the on-farm storage of fertiliser," she said.