Slight differences in the soil sample testing procedures carried out by the four laboratories approved for the Pilot Soil Sampling and Analysis Programme can lead to differences in soil test results, the Department of Agriculture has said.

The Department was responding to a query from the Irish Farmers Journal after a number of farmers said they had received soil test results which showed different index levels of phosphorus (P) compared to previous results.

Cawood Scientific Ltd, NRM Laboratories, IAS Laboratories and Farmeye are the four labs approved under the scheme.

The Department said that both NRM Laboratories and IAS Laboratories are accredited to an international standard and both of their standard operation procedures for the tests carried out for the scheme are in line with the legislation.

The spokesperson said that the P index depends on the level of available P in the soil solution.

“Therefore, this result can vary depending on the time of year the soil sample was taken, the representativeness of the sample along with the soil’s previous cropping history. At laboratory level, slight differences in the analytical procedure, even though in line with the statutory instrument, can lead to differences in soil test results.”

Farmers who have not taken soil samples in the past four years or at index 4 for P cannot apply P to land. Tillage farmers at index 4 for P, with high soil pH do have an allowance for P.

Over 7,500 farms have been sampled under the scheme, with approximately 90,000 soil samples taken to date.

Analysis of the test results is still ongoing with the standard suite of results currently being sent out to farmers within 10 days of sampling, the Department said. However, in some cases, farmers are waiting up to 20 days for results.

P allowance

Tillage or derogation farmers who have not taken soil samples in the past four years cannot apply P to land. The Department has said that farmers should have in date soil samples before applying P to land. If P is spread before results come back and P is at index 4 then the farmer could be subject to a penalty.