LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 6B: FISHIERIES, SOIL, AND EMERGY METHODS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Table 3. SOM pool evolution (Mg ha -1 year -1 ) in the baseline scenario during the vineyard lifespan (SOMvp:
SOM the end of vineyard planting; SOMpp: SOM at the end of pre-production period; SOMp: at the end of
production period)
SOM Vineyard planting Pre-production Production
before
planting
OMI OMo SOMvp OMI OMo SOMpp OMI OMo SOMp
46.41 1.56 2.59 45.38 0.40 0.58 45.20 0.48 0.58 45.10
The scenarios were established to evaluate the effects of different vineyard management techniques, using
manure distribution, residue management and inter-row grassing as variables. The scenario results,
showed in Fig. 2, have been expressed in kg CO2eq for FU and presented in two sections, with the vineyard
and winery phases being treated as separate.
kg CO2eq /FU
0.800
0.600
0.400
0.200
0.000
-0.200
-0.400
-0.600
Baseline S1 S2 S3 S4
Vineyard phase 0.156 -0.392 -0.366 0.130 0.168
Winery phase 0.543 0.543 0.543 0.543 0.543
Figure 2. Soil effect in the selected scenarios on total carbon footprint, showed in vineyard phase and winery
phase.
4. Discussion
The GWP of a 0.75 L bottle of red wine, was equal to 0.699 kg CO2eq, which is comparable to results
obtained in previous studies on wine CF (Notarnicola et al., 2003; Point 2009; Gazulla et al., 2010).
Here, the full SOM balance allowed us to evaluate vineyard management factors, such as fertilisation, grassing,
tillage intensity and residue management and, consequently, to understand the importance of soil accounting
in the CF of agricultural systems. The model used in this study revealed the positive impact of
cover crops on SOM content, as an alternative to the use of inter-row harrowing for weed control, as reported
by Parat et al., (2002) and Steenwerth and Belina (2008). Our results, ranging from -160 to 18 g C m -2 yr -1
for the S1 and S4, respectively, were comparable to the value of -15 g C m -2 yr -1 observed in a long-term
study (30 years) conducted in a Californian-Mediterranean climate (Kroodsma and Field 2006).
Furthermore, this model for SOM change estimation needs a Minimum Data Set (MDS) for agricultural
product CFs that accounts for soil carbon, thus establishing a standard for inventory. This MDS includes the
following: physical and chemical soil characteristics (clay, SOM and limestone contents), climate parameters
(average annual temperature), organic matter inputs and management practices.
5. Conclusion
In the context of the scientific debate on soil quality and SOM accounting, the approach proposed in this
study can be regarded as a simplified methodology among other existing methodologies. Our results highlighted
the need to consider soil in agricultural product CFs, indeed soil constitutes a major C pool in cropland,
meaning there is scope for large amounts of C to be gained or lost from soils as a consequence of management
practices. The method outlined in this study, based on the SOM balance, considered both OM input
into the soil and organic output lost in the form of natural and agriculture-induced mineralisation. This simple
and robust model was sensitive to changes in management practices.
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