ANALYTICAL AND METHODOLOGICAL DEVELOPMENT OF N-15 TRACER TECHNIQUE FOR SOIL-NITROGEN TRANSFORMATION STUDIES

The application of (15)nitrogen (N)-tracer technique in soil N-transfo rmation studies requires simultaneous determination of N-15/N-14 ratio and total N contents in large number of soil samples. Speciation of s oil N compartments by means of extraction and separation procedures is also required. An optical emission spectrometric method was elaborate d using atmospheric microwave induced plasma excitation which can be e asily coupled with separation techniques and is suitable for analysis of solid/liquid and gaseous samples. The method was applied to kinetic modeling N-cycles in mesocosm experiments using N-15-labelled fertili zers as N sources.