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

PARALLEL SESSION 1A: WATER FOOTPRINT 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Table 3. The eutrophication potential excluding gaseous emissions (EP) of beef and sheep meat (based on a
NZ weighted average), and milk produced in the Waikato and Canterbury regions respectively.
g PO4 3- -eq/kg unit Unit EP
Beef (NZ weighted average) LW 1 12.2
Sheep meat (NZ weighted average) LW 4.9
Milk in Waikato region FPCM 2 1.94
Milk in Canterbury region FPCM 1.49
1 Live Weight sold
2 Fat-and-Protein Corrected Milk
4. Discussion
A stress-weighted water footprint accounts for differences in water scarcity between the regions. The
stress-weighted WF of Australian beef produced in six different geographically defined production systems
varied between 3.3 and 221 litres per kg live-weight (Ridoutt et al., 2012), which was higher than the stressweighted
WF of NZ beef (0.2 L H2O-eq/kg LW). When converting live-weight into meat, using the factor
that animals contain approximately 40% of meat, this stress-weighted WF of NZ beef (0.51 L H2O-eq/kg
meat) was lower than the stress-weighted WF of beef produced in England (which was in the range of 15.1 -
20.0 L H2O-eq/kg meat, dependant on production system) (EBLEX, 2010). The stress-weighted WF of NZ
sheep meat (0.25 L H2O-eq/kg meat) was also lower than the stress-weighted WF of sheep meat produced in
the UK (which was in the range of 8.4 -23.1 L H2O-eq/kg meat, dependant on production system) (EBLEX,
2010). The WSI of NZ regions where livestock was produced varied between 0.01 and 0.013, whereas the
spatially averaged WSI for England was 0.27. However, the distribution of the livestock was not uniform,
and the weighted WSI for beef cattle was estimated at 0.19 (T. Hess, personal communication). The low
stress-weighted WF illustrates the benefits of NZ beef and sheep meat produced in regions with low water
stress levels from a possible marketing perspective.
The EP of the average Waikato and Canterbury dairy farm systems (1.9 g PO4 3- -eq/kg FPCM and 1.5 g
PO4 3- -eq/kg FPCM respectively) were much lower compared to the EP of organic (670 g PO4 3- -eq/kg FPCM)
and conventional milk (1080 g PO4 3- -eq/kg FPCM ) produced in the Netherlands (Thomassen et al., 2008).
This is mainly due to a difference in methodology, as the Dutch study included gaseous emissions.
Choice of allocation had little effect on the water footprint results. Economic allocation was applied when
dividing the water footprint between milk and meat. If biophysical allocation had been used it would have
decreased the stress-weighted WF by 7% and 11% for dairy farming in the Waikato and Canterbury respectively.
The stress-weighted WF of 0.14 L H2O-eq/kg milk solids for Waikato dairy farming was nearly one thousand
of the 94 L H2O-eq/kg milk solids for Canterbury dairy farming. The Waikato dairy WF was 10-fold
lower while the Canterbury dairy WF was 6.5-fold higher than the 14.4 L H2O-eq/ kg total milk solids reported
for non-irrigated South Gippsland, Australia (Ridoutt et al., 2010). This highlights the benefits, from a
water consumption perspective, of milk production in non-irrigated regions and of targeting water use efficiency
practices to dairy farming in irrigated regions.
5. Conclusion
We can conclude that the stress-weighted WF is a useful indicator to assess the impact of pastoral farming
systems on freshwater availability and EP is a feasible indicator to assess water degradation impacts of pastoral
farming systems, mainly resulting from leaching or runoff of eutrophying pollutants to waterways when
the gaseous emissions (such as ammonia, nitrous oxide and nitrogen oxides) are excluded. New Zealand has
large regions with low water stress, although seasonal droughts can occur in many areas. From an international
marketing perspective, beef and sheep meat produced in NZ, as well as milk produced in the rain-fed
region Waikato have a possible advantage for water consumption compared to overseas pastoral farming
systems.
The impact of NZ pastoral farming on freshwater availability can be reduced by practices that decrease
water use, increase feed conversion efficiencies, increase the use of non-irrigated feed supplements, and reduce
irrigation needs. The impact of NZ pastoral farming on water quality can also be reduced by efficient
nutrient management. Other water quality impacts of pastoral farming are relevant to consider in future studies,
e.g., the impact of microbial pollution on waterways.
References
Bayart, J-P., Bulle, C., Deschênes, L., Margni, M., Pfister, S., Vince, F., Koehler, A., 2010. A framework for
assessing off-stream freshwater use in LCA. International Journal of LCA. 15, 439-453
43