Analytical methods in15N research

Although the stable isotope15N is an indispensable tool in research to trace the fate of fertilizer nitrogen in soil/plant systems, the analytical methods used in this research are time consuming and prone to many errors. This paper outlines the methods used in an international program of nitrogen research coordinated by the International Fertilizer Development Center (IFDC). The different steps in the digestion, distillation, and isotope ratio analysis of15 N-labeled soils, plant material, and fertilizers are described. Details on the use of a series of controls to check the precision and accuracy of the methods are also given. It is hoped that this comprehensive description of procedures will encourage the expanded and proper use of15N. © 1982 Martinus Nijhoff/Dr W. Junk Publishers.