Use of fallout radionuclide measurements in soil erosion investigations

Accelerated erosion and associated soil degradation currently represent a serious global problem. Against this background, there is an increasing need to assemble reliable information on the rates of soil loss. Existing techniques for monitoring soil loss possess many limitations and a number of workers have explored the potential for using fallout radionuclides, and particularly 137Cs, to obtain estimates of the rates of soil erosion and deposition on agricultural land. In essence, the caesium technique provides a means of assembling retrospective information on medium term (about 35 year) rates of soil loss for an area and the spatial pattern of erosion and deposition involved, based on a single site visit. An example of the application of this approach to a cultivated field at Rufford Forest Farm, Nottinghamshire, United Kingdom, is provided to illustrate its value, and its potential for wider application is discussed. Further developments of the approach are also considered. Although, to data, few attempts have been made to exploit the potential for using other fallout radionuclides in soil erosion investigations, unsupported 210Pb and 7Be would appear to offer considerable promise. An example of the use of unsupported 210Pb measurements in a study of soil redistribution within a small field at Butsford Barton, Devon, UK, is presented and possible applications of 7Be measurements are considered. (author). 54 refs, 7 figs, 3 tabs