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| Titel |
Radionuclide determination techniques and spectroradiometry as tools to determine soil erosion |
| VerfasserIn |
E. Rodríguez, J. A. Suárez, C. Gascó, T. Schmid, M. Rodriguez |
| 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 |
250071447
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| Zusammenfassung |
| Natural (210Pbunsupported, 226Ra, 210Po and 7Be) and artificial (239,240Pu, 137Cs)
radionuclides are largely used as tools for studying and quantifying soil erosion. The
global fallout of artificial radionuclides derived from weapons testing that took
place during 1945’s and 1960’s was rapidly and firmly fixed in the soil surface,
allowing to calculate further soil erosion by comparing inventories at individual
sampling points with a reference inventory representing the local fallout input. This
procedure is complemented with the 210Pbuns inventory calculation as indicator
of the local average radionuclides deposition. Mathematical models, combining
radionuclides inventories and soil properties, are lately applied to estimate the erosion
rates.
Spectroradiometry, is a further technique to determine soil erosion processes, by
characterising soil surface reflectance values and relating these with soil properties such as
structure, texture, mineral composition and organic matter content obtained from the
laboratory analyses. The effect of erosion on these soils implies the presence of contrasting
soil horizons emerging at the surface. In this case, surface reflectance measurements of soil
samples are determined and associated to data obtained from the laboratory analyses. This
technique uses spectral characteristics that can be extrapolated from the field scale to satellite
coverage of an entire area.
The aim of this work is to use both radionuclides determination and laboratory
spectroradiometry techniques to evaluate soil erosion processes in well-developed soils
(Alfisols) and its spatial distribution in an agricultural area near to Camarena within the
Province of Toledo (Central Spain).
The methodology includes the test of the sampling devices during the sampling
campaign, the radionuclides analysis at different soil depths and the determination of their
activity concentration levels by means of gamma spectrometry, complementing with alpha
spectrometry to improve the measurement uncertainties. Furthermore, spectroradiometry is
implemented to associate soil surface reflectance measurements to soil properties related to
soil erosion processes. A further step in the methodology is the identification of spectral
characteristics which could then be used for the spatial analyses of soil erosion applying
remotely sensed data obtained either as airborne or satellite-borne images. As a result, a
spectral library could be compiled with spectra and soil analyses to obtain reference spectra
of characteristic surface conditions associated to soil erosion, but more researches are
needed.
Preliminary results, in a duplicate soil core from Camarena, 137Cs and 210Pbuns show
inventories of 576±77 (137Cs Bq-
m-2 ±1s), 677±88 (137Cs Bq-
m-2 ±1s) , 7561± 1439
(210Pbuns Bq-
m-2 ±1s) and 11292± 2598 Bq-
m-2 (210Pbuns Bq-
m-2 ±1s), respectively,
and are similar to those obtained in nearby areas with the same climatology. This shows that
erosion processes are taking place in these soils, however, ongoing work on the soil analyses
of the samples has to be completed before a complete interpretation can be carried out. |
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