A Fertiliser Product Survey has revealed significant discrepancies in fertiliser quality and highlighted that some bags are underweight.
The survey was carried by Yara UK who announced the findings at Grassland and Muck 2011.
Yara head of agronomy Mark Tucker said results of the 2010 survey, where twenty different commercially available fertilisers were tested, showed 38% of the bags tested were underweight and 39% failed to meet their declaration of analysis on standards such as nitrogen and phosphate content.
“This is the third time that Yara have carried out this extremely useful survey, and we have always been surprised at the lack of consistency in fertiliser quality – although we have seen some improvements in the results of this year’s survey, there is certainly a long way to go,” added Mr Tucker.
“We are trying to remind farmers that if they want an effective fertiliser they need to know the rates going on at all times because fertiliser is one of the single biggest inputs the farmer will make in the first place.”
He said the survey also revealed a “serious lack of traceability” in UK fertilisers with 61% of the products tested lacking traceability to the batch they came from.
Mr Tucker added: “Yara bag development experiments suggest bags containing blends should have a liner thickness of 85 plus microns because this prevents liner puncture and water ingress from the base during storage, but the survey showed that only 18% of bags had a thickness of greater than 85.”