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| Titel |
Improving the soil organic carbon and pH VisNIR calibrations within the field of uniform soil cover by extending the model with the samples from the nearby locations |
| VerfasserIn |
Krzysztof Kuśnierek, Marco Nocita, Rachel Opitz, Fekerte Yitagesu, András Zámolyi |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250057583
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| Zusammenfassung |
| The potential of using VisNIR spectroscopy to estimate soil properties has been widely
reported. The measurements of the electromagnetic radiation reflected from a soil sample in
the region between 400 and 2500 nm, reveal the information about the physical and chemical
composition of soil. Generally, local calibrations of soil properties using VisNIR
spectroscopy outperform regional and global calibrations in terms of prediction errors and
produce results comparable to the traditional SOC measurement techniques. Nevertheless,
examples of poor calibration results of soil properties within agricultural fields having
uniform soil cover and a relatively small range of concentrations of the analyzed constituent
have been published.
In this study the the potential for improving the calibration of SOC content and pH levels
by incorporating the soil samples collected from other locations in the region in question into
the calibration model is investigated. This is a preliminary study conducted within the
EUFAR’s ADDRESSS project on the application of airborne hyperspectral and LiDAR
data in soil monitoring. In the current stage a limited-extent soil survey has been
conducted.
A sample field of 35 ha (centroid: 46o56’43”N, 17o43’24”W) with a uniform soil cover of
cambisol developed over limestone and dolomite was selected in the Balaton Uplands
National Park in Western Hungary near Tihany. 20 soil samples were collected there. The
samples were air dried, ground, and sieved through a 2mm sieve. SOC content
was characterized using the dichromate oxidation (Walkley Black’s) method and it
ranged from 0.85 to 2.14 g kg-1. Soil reaction was measured in 1:1 KCl solution
and the pH values ranged from 6.34 to 7.34. Spectral measurements of the soil
samples were conducted using ASD Fieldspec 3 spectrometer in the laboratory
conditions.
A cross-validated calibration VNIR model provided the estimated concentration of the
analyzed soil properties which were compared to their reference values. Additionally, the
spatial distributions of both constituents were obtained using kriging interpolation and
measured and predicted values were compared. Additionally, 11 soil samples were collected
from three other locations within the region. They represent various soil types, developed
over a tertiary tuff and triassic limestone. The introduction of additional soil samples
extended the concentration range of SOC (0.85 to 3.20 g kg -1) and pH (6.34 - 7.49). The
calibration results improved substantially, suggesting that extending the within-field model
with the samples from nearby locations enhances the modeling of soil constituents. |
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