『Abstract
Soil loss evaluation by means of radioisotopic content measurements
represents a promising technique, half-way between field surveys
and theoretical models, which still suffers from its practical
limits when applied at basin scale. A main limit is represented
by the costs of field investigations and laboratory investigation
on the high number of soil samples required by a traditional sampling
scheme, such as regular grid or transects. A non-conventional
soil sampling scheme was tested with the aim to consider a relative
scanty number of soil samples and to verify the feasibility of
this technique on large areas. This scheme was based on the hypothesis
that land analysis and classification could point out areas characterised
by homogeneous behaviour with respect to the 137Cs
deposition and transmission model. A Geographic Information system
(GIS)-aided procedure allowed to classify the selected basin area
in pedo-morphological units, representative of the different pedologic,
morphologic and land-use conditions, to locate few sampling points
for each unit. Outcomes pointed out a low correlation between
137Cs contents and soil physical and compositional
characteristics. Nevertheless, the isotopic methodology allowed
to estimate a total soil loss value at basin scale almost consistent
with both observed data, given by reservoir sedimentation measurements
and estimates from the application of the RUSLE model. Thus, the
results can be considered encouraging and they allow to deem that
the isotopic methodology can be refined in order to account for
erosion and deposition processes even at river basin scale and
with a limited number of soil samples.
Keywords: 137Cs; Soil erosion; River basin; GIS; Sicily』
Introduction
Study area
Materials and methods
Basic principles
Conversion models
Sampling methodology
Analytical techniques
Results and discussion
Geochemistry of sampling scheme with measured 137Cs
content
Comparison with RUSLE and observed data
Conclusions
Acknowledgments
References