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| Titel |
Soil organic matter prediction using environmental factors |
| VerfasserIn |
I. Oueslati, P. Allamano, P. Claps, E. Bonifacio |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028742
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| Zusammenfassung |
| Organic matter is one of the most important properties affecting soil chemical and physical
fertility, but it influences also soil hydrologic parameters. It is easily measured by chemical
analyses, but in large scale studies its prediction is desirable. This study aims at predicting the
spatial distribution of the soil organic matter concentration (SOM) in forest topsoils in
Piedmont (North West Italy) using continuous predictors (in forms of auxiliary maps). As
predictors we selected: the digital elevation model (DEM, 50 meter resolution), the mean
annual precipitation, the soil dryness index and normal difference vegetation index (NDVI, 1
km resolution). Using the Geographic Information System SAGA, the terrain attributes were
computed from the DEM, namely are: elevation, slope, aspect and mean curvature associated
with hydrological parameters namely, the compound topographic index (CTI) and stream
power index (SPI). From the long term monthly average of NDVI the mean annual value
and the coefficient of variation (CV) were also derived. This data set was used to
estimate the SOM concentration by regression analysis. To test the relationship
between the SOM and the environmental variables, 66 soil profiles were used. Several
variables were found to be significantly correlated with SOM concentration: elevation,
slope, mean NDVI, CV(NDVI), precipitation and dryness index, with correlation
coefficients, r, of the linear regressions ranging from 0.12 to 0.63. However, only
precipitation and mean NDVI were retained when a stepwise multiple regression was used.
Although these two predictors contribute only partially to explain SOM variability
(R2=0.42). The importance of vegetation is clearly depicted by the significant effect of
NDVI, while the precipitation may contribute to the explanation in a less direct way
because of the complex links between climate and organic matter transformation in
soils. |
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