RADIOTRACER METHODS TO DETERMINE ROOT DISTRIBUTION - A REVIEW

This paper reviews radiotracer techniques that have been used to determine plant root distribution. General methods of radionuclide solution preparation, injection, sampling, and sample counting are described. The techniques provide qualitative information on whether living, functional roots of a specific plant are present at a particular location around the plant, but not on root density or biomass. The soil injection technique has been used to determine the volume of functional roots or the maximum lateral spread at various depths, including maximum depth. The plant stem injection technique has been used, with less success, to determine the distribution of living roots, including those that are dormant.