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| Titel |
Relationship between 210Pbex and soil characteristics in Mediterranean hillslope |
| VerfasserIn |
L. Gaspar, A. Navas, J. Machín |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067231
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| Zusammenfassung |
| Natural occurring fallout 210Pb (half live, 22.2 yr) offers the potential for use as a radiotracer
of soil movement in a similar manner to 137Cs in diverse agricultural landscapes of the world.
The purpose of this study was to investigate the content of 210Pbex, physico-chemical soil
properties and physiographic factors of Mediterranean mountain hillslopes in order to infer
the relationship between these properties analyzed in selected cultivated and undisturbed
soils. The study area is located in a subhumid Mediterranean agroecosystem in the central
part of the Pyrenees. Along two hillslope transects a total of 31 soil cores were
collected with different land uses, soil types, lithologies, altitude, orientation and slope
gradient.
The 210Pbex mass activities ranged between 0.8 and 54.7 Bq kg-1 and the 210Pbex
inventories varied between 318 and 7298 Bq m-2. The Anova test indicated significant
differences in the mean of 210Pbex mass activities for different land uses and ranges of
altitude, while significant differences were found in the mean of 210Pbex inventories for
different land uses, slope gradients, ranges of altitude and different soil types. Significant
positive correlations were found between 210Pbex mass activity and total organic carbon
(TOC) and stoniness, respectively, but inverse relation was observed with clay content despite
expected. Nevertheless, when differentiating between land uses, in uncultivated soils the
correlations decrease and in cultivated soils no significant correlations were found. On the
other hand, no significant correlations were found between the 210Pbex inventories and soil
properties analyzed. Principal component analysis (PCA) and Cluster analysis were used to
generate a hypothesis that the distribution pattern of radioisotope was influenced by the
variation in soil properties and physiographic factors. PCA results showed that
TOC, stones and altitude were the major soil factors responsible for variations of
210Pbex mass activity in soils. The Cluster analysis showed results similar to PCA.
Furthermore, a preliminary regression and GLM models have been developed in
order to infer the content of 210Pbex in soils based on sets significant soil properties
more easily measurable. However, more data would be required to develop robust
models.
These relationships can be used to determine the approximate content of 210Pbex in
Mediterranean soils. The results suggest that the content of 210Pbex in soils is strongly
affected by land use and TOC content. Further research has to be done for better
understanding the role of soil properties in the distribution of 210Pbex, which is
relevant for applying 210Pbex to assess soil erosion in Mediterranean agroecosystems. |
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