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| Titel |
Integrating soil map delineations properties and land use into soil carbon density assessment at regional scale (Emilia Romagna, Italy) |
| VerfasserIn |
F. Ungaro, C. Calzolari |
| 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 |
250020805
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| Zusammenfassung |
| Accurate estimates of soil organic carbon (SOC) at regional scale are important to estimate
the potential of soils as C reservoir. Different approaches can be used resulting in different
degree of uncertainty associated to the estimates (Ungaro et al, 2005). Among the major
source of uncertainty, land use, soil variability and bulk density for the reference depth are
those with the greater influence on the final SOC stock estimation (Meersman,
2007).
In order to reconstruct the spatial patterns of SOC at the landscape scale and to reduce
the uncertainty associated to SOC stock estimates, an hybrid approach has been
developed, combining the properties of the delineations of the regional 1:50.000
soil map with a geostatistical procedure (sequential Gaussian simulation). In the
alluvial plain area of Emilia Romagna (10,734 km2) in Northern Italy, the available
spatially explicit soil data (17,652 horizons from 3,302 profiles,), from 237 soil
typological units, have been referred to 13 soil functional groups, divided in 42
subgroups. Based on the main geomorphic and pedogenetic processes, the soil
functional groups and subgroups are defined in terms of top-soil textural classes (texture
family), drainage class, slope, presence of organic materials (O horizons), flooding
occurrence, origin of the parent material and presence of limestone. In order to take into
account the influence of land use, the observations within each functional group have
been further divided according to the different agricultural districts of the plain,
characterized by different dominant land uses. The SOC density (Mg ha-1) of the 100 cm
reference depth has been calculated as a weighed sum of the values calculated for
each horizon., using a set of locally calibrated pedotransfer functions (Ungaro,
2007) whose inputs beside organic C are the sand, silt, and clay textural fractions
The average values of each soil functional (sub)group of each district were used to
assign a SOC density (Mg ha-1) value to each delineation of the 1:50.000 map.
These values were then used to condition the outcomes of geostatistical parametric
simulations. The resulting map shows, quantitatively and explicitly accounting for
spatial uncertainty, the strong dependence of SOC stock on the main agricultural
and pedological landscapes. The results show that the pattern of local land use in
combination with soil type has a relevant impact on the SOC stored in cropland. The
overall pattern is clearly affected by dominant land use at district level, with the
areas characterized by a dominance of permanent grassland storing nearly twice as
much the areas dominated by orchards, and by local soil conditions, in particular
along the Apennines’ foothills, in the lowlands of the plain and in the reclaimed
areas of the ancient Po river delta. The average SOC density is 153.27 |
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