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| Titel |
Prefractal scaling of apparent soil moisture estimated from vertical planes of Vertisol pit images |
| VerfasserIn |
R. Cumbrera, A. M. Tarquis, G. Gascó, H. Millan |
| 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 |
250071418
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| Zusammenfassung |
| Image analysis could be a useful tool for investigating the spatial patterns of apparent soil
moisture at multiple resolutions. The objectives of the present work were (i) to
define apparent soil moisture patterns from vertical planes of Vertisol pit images
and (ii) to describe the scaling of apparent soil moisture distribution using fractal
parameters.
Twelve soil pits (0.70 m long x 0.60 m width x 0.30 m depth) were excavated on a bare
Mazic Pellic Vertisol. Six of them were excavated in April/2011 and six pits were established
in May/2011 after three days of a moderate rainfall event. Digital photographs were taken
from each Vertisol pit using a KodakTM digital camera. The mean image size was 1600 x 945
pixels with one physical pixel - 373 μm of the photographed soil pit. Each soil
image was analyzed using two prefractal scaling exponents, box counting (capacity)
dimension (DBC) and interface fractal dimension (Di), and three prefractal scaling
coefficients, the total number of boxes intercepting the foreground pattern at a unit scale
(A), fractal lacunarity at the unit scale (Î1) and Shannon entropy at the unit scale
(S1).
All prefractal scaling parameters identified significant differences between both sets of
spatial patterns. Fractal lacunarity was the best discriminator between apparent soil moisture
patterns. Soil image interpretation with prefractal parameters can be incorporated within
site-specific agriculture toolbox. While fractal exponents condense information on space
filling characteristics of the pattern, prefractal coefficients represent the investigated soil
property as seen through a higher resolution microscope. In spite of some computational and
practical limitations, image analysis of apparent soil moisture patterns could be used in
connection with traditional soil moisture sampling, which always renders punctual
estimates.
Key words: Image analysis, fractal scaling, apparent soil moisture, Vertisols
Acknowledgements
This work has been partially funded by project AGL2010-21501/AGR (MICINN) |
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