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
Table 1. Soybean cultivation systems: main inputs and yields (values per ha and year).
No-tillage (Cavalett and Ortega, 2009, 2010) Tillage (Jungbluth et al., 2007)
Pesticides 8.0 kg 1.47 kg a
Limestone 375 kg -
Fertilisers 33.8 kg P and 65.4 kg K 30 kg P2O5 b and 30 kg K2O
Diesel 65 L 65 L
Electricity 122 MJ -
Soybean production (yield) 2830 kg 2544 kg
a 2,4-D (51%), glyphosate (37%), monocrotofos(8%) and endosulfan (4%).
b Diammonium phosphate (45%), single super phosphate (29%), triple super phosphate (16%), phosphate rock (5%) and ammonium
nitrate phosphate (5%).
Two climate regions (tropical moist and warm temperate moist) and a low activity clay soil were considered
for LUC emissions calculations. GHG emissions from carbon stock changes caused by LUC were calculated
based on the carbon stock associated with each Reference land use, CSR (previous land use types)
and the carbon stock associated with the soybean production systems considered, CSA (Actual land use),
following IPCC Tier 1 and European Union Directive on Renewable Energy (EC, 2009, 2010; IPCC, 2006).
Soil organic carbon (SOC) calculated and the above and below ground vegetation carbon stock in living
biomass and in dead organic matter (CVEG) adopted from EC (2010) are presented in Fig. 1 for the various
reference land use (SOCR and CVEGR) and for the soybean plantations (SOCA and CVEGA).
Carbon stock (t C/ha)
120
100
80
60
40
20
0
Managed
forest
Improved
management
Moderatly
degraded
Severely
degraded
Tillage No-tillage Improved
management
Savannah Soybean plantation Managed
forest
Perennial crop
(reduced
tillage)
Moderatly
degraded
Figure 1. Carbon stocks of previous land use (SOCR and CVEGR) and of soybean plantation (SOCA and CVEGA)
for 2 climate regions in Brazil.
Soybean produced in Brazil is transported from plantation to the Paranaguá port by road (897 km) and by
transoceanic freight ship over 8393 km to Lisbon port (near the oil extraction plant). GHG emissions related
with the soybean transportation were calculated based on these average distances and the factors given by
Spielmann et al., (2007). Regarding the soybean oil extraction process (co-produced with soybean meal), a
LC inventory and modelling was implemented based on average data collected from Portuguese industry.
Electricity and heat requirements are 0.16 MWh/t oil and 3292 MJ/t oil, respectively. Natural gas and heavy
fuel oil are used to produce heat. Electricity is obtained from the grid and produced onsite from a natural gas
combined heat and power (cogeneration) plant. GHG emissions from electricity and heat production were
calculated based on EC (2009), Faist Emmenegger et al., (2007), Frischknecht et al., (2007) and Jungbluth et
al., (2007). The GHG emissions from hexane production have also been considered based on the quantity
consumed (7.9 kg/t oil) and the GHG emission factor (Jungbluth et al., 2007). Since a valuable co-product is
obtained from the soybean oil extraction system, the soybean meal, there is a multifunctional issue that
should be solved. Several scenarios based on alternative allocation and substitution approach were used for
dealing with this co-production, as detailed in the next sub-section.
2.1. Multifunctionality in the soybean oil process: allocation and substitution scenarios
Severely
degraded
Tillage No-tillage
Grassland Soybean plantation
CSR CSA CSR CSA
Tropical, moist (Brazil, Central -West) Warm temperate, moist (Brazil, South)
The ISO standards provide a hierarchical approach for handling co-products (ISO, 2006): avoiding allocation
(by dividing the unit process to be allocated into sub-processes or expanding the product system to in-
CVEG
SOC
CS R: Carbon stock associated with the reference land use
CS A: Carbon stock associated with the actual land use
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