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

PARALLEL SESSION 3A: LAND USE CHANGE 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
The average soil C emission factor over the Agri-BALYSE reference period is then calculated for grasslands
and annual crops. It will be applied to each ha concerned.
2.3. Method to estimate crop-specific soil C dynamics from LUC
In order to take into account the regional specialisation of agriculture observed in France, we have tried to
develop a more accurate method. This method should allow attributing LUC more to the crops which are
most involved in LUC to and from permanent grassland.
The first steps are as for the simplified method. The data from Teruti-Lucas network and French Soil Survey
Network are used to determine: i) permanent grassland and annual crop areas having undergone LUC
less than 20 years ago for each year of the Agri-BALYSE reference period: 2005-2009.and ii) average soil C
stock for both land uses.
Unlike the previous method, which is implemented at the scale of mainland France, this method is implemented
at the scale of mainland France’s 22 administrative regions to calculate emissions of soil C at the
regional scale. Negative emissions (i.e. C sequestration) are attributed to the areas in permanent grassland,
while positive emissions are attributed to areas in annual crops, yielding regional emissions for permanent
grassland and annual crops. The next step is to distribute emissions among crops within each region according
to the relative area of each crop in the administrative region over the 2005-2009 period, using the statistic
data base of the Office of Statistics and Studies (SSP) of the French Ministry for Food, Agriculture and Fisheries
(AGRESTE, 2012). Finally a crop-specific emission factor for mainland France was calculated from
regional crop emission factors as a weighted average.
3. Results and discussion
In a first approach, the simplified method was implemented and emission factors for permanent grassland
and annual crops were calculated (Table 4).
Table 4. Total estimated areas of LUC from grassland to annual crops and from annual crops to grassland
and CO2 emissions per year per ha of annual crop and grassland in mainland France. Average total areas of
annual crops and grassland and average CO2 emissions from LUC expressed per ha of the total area of annual
crop and grassland.
Land-Use Change Area (ha) Emission factor (t CO2/ha)
Grassland to annual crops,
2005-2009
3 222 728 3.40
Annual crops to grassland, 2 764 221 - 3.16
2005-2009
Total annual crops, 2005-2009 16 686 248 0.66
Total grassland, 2005-2009 11 139 626 - 0.78
This was the first step to take in consideration carbon soil dynamics in Agri-BALYSE. However, even if:
i) it is in accordance with one of the aims of Agri-BALYSE, i. e. the identification of a set of consistent and
consensual methods for LCAs of agricultural products; ii) it is consistent with ILCD recommendations; iii)
this methodology, based on IPCC 2003, has been used for several international studies/recommendations
(BSI, 2011; Gerber et al., 2010; IDF, 2010; Leip et al., 2010; Commission Européenne, 2010); this method
lacks sophistication, as it yields a single emission factor for all annual crops. Since the 70’s, a strong trend of
regional specialisation of agricultural production systems has been observed in France (Dussol et al., 2003).
Three main specialised regions can be distinguished: annual crops (Paris Basin and North); livestock production,
involving grassland and annual crops (East, West, Massif Central and north of Alps); perennial crops
and vegetables (South-West and South East). The proportion of permanent grassland in the agricultural area
varies greatly between these regions. Therefore attributing the same emission factor to all annual crops is a
major simplification of reality. For this reason we propose a more accurate method which takes in consideration
spatial distribution of grasslands and annual crops across mainland France (Table 5). These emission
factors take into account that some annual crops, mainly produced in regions where permanent grassland is
rare, are less involved in LUC.
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