Six soils cultivated with cardoon were sampled within 10 km of Porto Torres
area, (Sassari, Sardinia Region, Italy) and assessed for required parameters to make
possible the model running (Table 1).
The mineralisation coefficient (k 2 ) for a “derived soil” from parameter averages,
was calculated according to Castoldi and Bechini [11], considering the lack of
irrigation (I = 1). The amount of resistant SOM fraction was estimated according to
Boiffin et al. [15] or applying BSI [10,14] on cardoon above-ground residues:
wheat 0.08, bean 0.1, and roots 0.15; above-ground cardoon was 0.18 experimentally estimated from compositional analysis. Even contribution of cardoon
basal leaves and renewal of roots was calculated and computed in the model. This
issue will be the subject of a specific forthcoming publication.
Cardoon residues were harvested leaving on the ground 10% of above-ground
biomass (w/w as dry matter).
Two scenarios were considered: “compost” and “no compost”. Compost scenario planned for 20 Mg/ha compost application before cardoon sowing and
15 Mg/ha on the crop during the 4th year of cultivation. Compost incorporation
applied dry matter (dm) 50% (w/w), Nitrogen (N) content 1.8% (w/w dm), organic
carbon 48% (w/w dm), BSI 0.53, k 1 0.25 [16]. In “no compost” scenario the
contribution of OM is represented only from the cardoon above-ground biomass
(i.e. 10%) that remains in soil after harvesting.
Cardoon C footprint was estimated using BioGrace tool [17] and IPCC [18]
methodology applying 20-year time-horizon to assess global warming potential for
CO 2 CH 4 and N 2 O [19]. In particular following IPCC [18], GHG emissions fixed in
the industrial production process of urea was taken into account along with direct
and indirect N 2 O emissions due to N-synthetic and organic fertilisers, crop residues
Table 1 Parameters implemented in the model for different soil samples (from 1 to 6) and if their
contribution in increasing (+) or containing (−) the SOM stock mineralisation rate, according to the
model
Sample/parameter
SOMS
correlation
1
2
3
4
5
6
Mean ± st.
dev.
Mean annual
temperature (°C)
+
16.7 16.7 16.6 16.7 16.8 16.7 16.7 ± 0.1
Soil organic matter (%
w/w)
+
2.10 2.45 2.03 2.59 2.76 2.38 2.39 ± 0.31
Bulk density (g/cm
3
)
+
1.32 1.28 1.31 1.26 1.26 1.26 1.28 ± 0.03
Coarse materials (% v/v) −
0.00 0.13 0.17 0.17 0.12 0.02 0.10 ± 0.07
Clay (g/kg)
−
367 517 458 567 400 121 405 ± 82
Carbonates (g/kg)
−
163 37
3
79
9
616 151 ± 66
136
F. Razza et al.
area, (Sassari, Sardinia Region, Italy) and assessed for required parameters to make
possible the model running (Table 1).
The mineralisation coefficient (k 2 ) for a “derived soil” from parameter averages,
was calculated according to Castoldi and Bechini [11], considering the lack of
irrigation (I = 1). The amount of resistant SOM fraction was estimated according to
Boiffin et al. [15] or applying BSI [10,14] on cardoon above-ground residues:
wheat 0.08, bean 0.1, and roots 0.15; above-ground cardoon was 0.18 experimentally estimated from compositional analysis. Even contribution of cardoon
basal leaves and renewal of roots was calculated and computed in the model. This
issue will be the subject of a specific forthcoming publication.
Cardoon residues were harvested leaving on the ground 10% of above-ground
biomass (w/w as dry matter).
Two scenarios were considered: “compost” and “no compost”. Compost scenario planned for 20 Mg/ha compost application before cardoon sowing and
15 Mg/ha on the crop during the 4th year of cultivation. Compost incorporation
applied dry matter (dm) 50% (w/w), Nitrogen (N) content 1.8% (w/w dm), organic
carbon 48% (w/w dm), BSI 0.53, k 1 0.25 [16]. In “no compost” scenario the
contribution of OM is represented only from the cardoon above-ground biomass
(i.e. 10%) that remains in soil after harvesting.
Cardoon C footprint was estimated using BioGrace tool [17] and IPCC [18]
methodology applying 20-year time-horizon to assess global warming potential for
CO 2 CH 4 and N 2 O [19]. In particular following IPCC [18], GHG emissions fixed in
the industrial production process of urea was taken into account along with direct
and indirect N 2 O emissions due to N-synthetic and organic fertilisers, crop residues
Table 1 Parameters implemented in the model for different soil samples (from 1 to 6) and if their
contribution in increasing (+) or containing (−) the SOM stock mineralisation rate, according to the
model
Sample/parameter
SOMS
correlation
1
2
3
4
5
6
Mean ± st.
dev.
Mean annual
temperature (°C)
+
16.7 16.7 16.6 16.7 16.8 16.7 16.7 ± 0.1
Soil organic matter (%
w/w)
+
2.10 2.45 2.03 2.59 2.76 2.38 2.39 ± 0.31
Bulk density (g/cm
3
)
+
1.32 1.28 1.31 1.26 1.26 1.26 1.28 ± 0.03
Coarse materials (% v/v) −
0.00 0.13 0.17 0.17 0.12 0.02 0.10 ± 0.07
Clay (g/kg)
−
367 517 458 567 400 121 405 ± 82
Carbonates (g/kg)
−
163 37
3
79
9
616 151 ± 66
136
F. Razza et al.