Use of 137Cs in quantitative evaluation of soil erosión and sedimentation in a Palehuniult, located at the 9th Región

Abstract

The ¹³⁷Cs technique used for estimating mean soil redistribution rates is based on the uniform deposit of thiis anthropogenic radionuclide in a climatic zone and its quick adsorption by clay particles.
In order to evaluate the potential use of ¹³⁷Cs technique in soils of South Chile, mean soil erosión and sedimentation rates and its spatial distribution were determined in a Palehumult of the 9^th Región, based on tlie spatial distribution of the ¹³⁷Cs inventory. For this purpose models were adapted to the ¹³⁷Cs-deposition pattem, and soil and climatic conditions of the study área. The erosión/ sedimentation rates and their spatial distribution obtained by three different models were very similar. The highest erosión rates (10-30 t ha^-1 y^-1) were determined at the zones of maximal slope of the landscape, and the highest sedimentation (7-15 t ha^-1 y^-1) at footslope in water flow concentration sites. The results obtained has been validated by pedological observations and quantifícation of sediment flux in erosión plots. These results suggest that the ¹³⁷Cs technique is a good altemative to determine soil redistribution rates under the soil and climatic conditions selected.