http://www.legislation.gov.uk/nisr/1991/540/schedule/2/crossheading/determination-of-ammoniacal-nitrogen/paragraph/1n4/madeThe Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1991Local GovernmentGovernment Printer for Northern Ireland2016-09-06AGRICULTURESCHEDULE 2METHODS OF ANALYSIS2.DETERMINATION OF AMMONIACAL NITROGENSCOPE1This method is for the determination of ammoniacal nitrogen.