Environmental Engineering Reference
In-Depth Information
promoted. In fact, it is not realistic to hypothesize that these changes will occur in
a short lapse of time, therefore leading to much smaller increments than those we
estimated for the considered mitigation options. Besides, it has to be considered
that the SOC sequestered in cropland soils is not permanent. By changing agricul-
tural management or land-use, soil carbon is lost more rapidly than it can accu-
mulate (Smith et al. 1996 ). For soil carbon sequestration to occur, the land-use or
land-management change must also be permanent.
8.5 Soil Carbon Storage and Projections Under Climate
Change Conditions in Sardinia Croplands
In this paragraph, a regional estimation of SOC pools in Mediterranean cropland
soils is showed. RothC, a dynamic simulation model of carbon turnover in the soil
(Coleman and Jenkinson 1996 ) was linked to a GIS soil and climate database to (i)
assess the actual SOC stocks in croplands; (ii) evaluate the model performance by
comparison of modeled and observed SOC data; (iii) estimate the future SOC pool
variation under a climate change scenario.
The present study was performed in the Sardinia region. Sardinia is the sec-
ond largest island in the Mediterranean Sea (about 24,090 km 2 ). The climate is
Mediterranean, sub-arid type with a warm summer, mild winter, and a remark-
able water deficit from May to September. Most of the rainfall (approximately
700 mm/year) occurs in fall and winter. The average annual temperature is 15 °C,
while the average minimum one is 7 °C, and the average maximum temperature
is 28 °C. Almost 28 % of the total island soils are represented by a mix formed
by rock outcrops and Leptosols (Eutric, Dystric e Lithic), spread throughout the
territory and especially on hard rock (metamorphic, intrusive, effusive, dolomitic
and limestone), mostly in steep areas with irregular shape and free of tree cover
or shrublands. The surface with agricultural use (including crops, sown field and
orchards) is equal to the 38 % of the whole island surface (AA.VV 2008 ). The
two main tree crops are olive groves (48,779 ha) and vineyards (24,693 ha). The
remaining tree crops cover less than 12,000 ha. The herbaceous irrigated crops
are the 26.1 % of the island surface. Table 8.1 reports the Land Use categories
included in the present analysis.
Table 8.1 Agricultural land use categories* where the analysis was performed
Land use
Surface (ha)
Surface
(%)
Permanent irrigated and irrigated arable lands
628,326
26.1
24,693
1.0
Vineyard
Olive groves
48,779
2.0
701,798
29.1
Total
* Source Land use map of Sardinia 2008
 
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