The results of a Teagasc trial on protected urea have been published, which show “further reassurance that protected urea can be part of a toolbox of solutions for Irish agriculture”, the agricultural authority has revealed.
A new scientific paper was published this week with results from a trial on using protected urea on the Teagasc farm at its Environment research centre in Johnstown castle.
Some concerns were raised by industry about the potential for protected urea residues to appear in milk, Teagasc notes.
The published paper details the development, at Teagasc, Ashtown, of a highly sensitive and validated analytical method for the detection of the urease inhibitor NBPT and NBPTo in the matrix of milk.
The paper also details the sampling and testing of milk from the Teagasc Johnstown dairy herd, where protected urea is used as the N source, for residues using this new method.
Dr. Martin Danaher, principal research officer in the Teagasc Food Safety Department, said that residues were not found in bulk tank or individual cow milk samples from dairy cows grazing pastures fertilised with urea protected with the urease inhibitor NBPT.
The limit of quantitation of the method was two parts per billion. The method was 25 times more sensitive than previous methods, the authority says.
Commenting, Dr. Patrick Forrestal, senior research officer in the Teagasc Crops, Environment and Land Use Programme, said:
“Extensive trials by Teagasc over the past nine years have shown protected urea to be a solid yield performer in Irish grassland and thus a reliable fertiliser option for farmers.
“Not finding residues in the milk of cows grazing pastures fertilised with protected urea, even when using a highly sensitive method, gives further reassurance that protected urea can be part of a toolbox of solutions for Irish agriculture to meet the challenges ahead,” Forrestal added.
Farmers in Ireland are being encouraged to switch from using CAN (calcium ammonium nitrate) fertiliser to protected Urea, as part of the sectors drive to reduce emissions from agriculture.
Dr. Karl Richards, Head of the Teagasc Environment, Soils and Land Use Research Department said:
“Protected urea is a key practice change in the Teagasc MACC [Marginal Abatement Cost Curve] that farmers can simultaneously reduce greenhouse gas emissions, improve the carbon foot print of their products and reduce fertiliser costs.
“This research is critically important to reassure the dairy industry that no residues were found in milk,” Dr. Richards concluded.