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

PARALLEL SESSION 6C: POULTRY AND PORK PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
was an increased demand for both supplements and enzymes compared to scenario one. The supplements
were modelled using ecoinvent processes (Ecoinvent, 2007). Phyzyme was modelled using a fixed GHG
emissions rate of 5.0 kg CO2 per kg enzyme produced (Dalgaard, 2011). Axtra XAP was modelled based on
production formulas and represents 90-100% of the actual ingredients and materials. Data for energy and
material use from the production of Axtra XAP was from the enzyme factories’ production records. Data on
the ingredient production was from Ecoinvent (2007), LCA food database (2003), suppliers and literature.
Transportation of raw materials was included for the most important materials. The end-use of the manure
was assumed to be as an organic fertiliser. The increased digestibility of the feed ingredients, facilitated by
Axtra XAP, resulted in less methane emissions from the manure in scenario two compared to scenario one
from both the broiler sheds and the manure storage. The broiler’s increased nitrogen retention in scenario
two compared to scenario one, again as a result of the use of Axtra XAP, results in less nitrogen in the manure.
This leaded to decreased nitrous oxide emissions from the sheds, the manure storage and from the
fields. However, when the manure contained less nitrogen it then substituted less marginal nitrogen fertiliser.
Thereby, the demand for the marginal nitrogen fertiliser increased. In the study, ammonium nitrate was assumed
to be the marginal nitrogen fertiliser, as it is the dominant nitrogen fertiliser in Europe (Sonesson et
al., 2009). Inorganic nitrogen fertiliser was modelled as ammonium nitrate. It was assumed that poultry manure
offsets the use of inorganic nitrogen with 70% (FVM, 2011). Data used to model the processes was
based on three databases; the ecoinvent database (Ecoinvent, 2007), the LCA food DK database (LCA food,
2003) and Danisco’s database (Dalgaard, 2011). When using different databases, there will be unavoidable
differences in the datasets and methodological choices. However, the majority of all the feed ingredients
were based on data from the Danisco database (97% of the total weight) resulting in data and methodological
consistency.
3.2 Results of the life cycle impact assessment
The results are presented in Fig. 2. The results of the LCA are given as a difference between scenario one
and scenario two per FU, representing the changes induced by Axtra XAP. The total reduction in GHG emission
per FU when applying Axtra XAP amounts to 90.5 g CO2 eq. (dark blue column).
Figure 2. Changes in GHG emission caused by the use of Axtra XAP in scenario two compared to scenario
one. The negative value indicates a decrease in GHG emissions and a positive value indicates an increase in
GHG emissions in scenario two compared to scenario one.
The use of Axtra XAP in the feed formulation resulted in decreased GHG emissions from pig and poultry
fat, meat and bone meal, soybean meal and corn, and increased GHG emissions from DDGS and the supplements
amounting to a reduction in GHG emissions of 90.0 CO2 eq. per FU. The increased GHG emissions
from the supplements were mainly driven by the increased level of dicalcium phosphate in scenario two. The
use of Axtra XAP resulted in an increase in GHG emissions of 0.85 g CO2 per FU (red column). GHG emissions
from manure management and storage were reduced by 10.4 g CO2 eq. per FU (green column). GHG
emissions from the use of the manure as a crop fertiliser were also reduced, as a consequence of the lower
nitrogen content in the manure. However, when less organic nitrogen was emitted by the broiler to be used as
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