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

GROUP 2, SESSION A: CARBON OR WATER FOOTPRINTS, SOIL, BIODIVERSITY 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
54. Soil and biogenic carbon accounting in carbon footprint: potential
and challenges
Edouard Périé 1,2,3,* , Sarah J. McLaren 1,3 , Brent E. Clothier 2,3
1 Massey University, Palmerston North, New Zealand, 2 New Zealand Institute for Plant & Food Research
Ltd, Palmerston North, New Zealand, 3 New Zealand Life Cycle Management Centre, New Zealand, Corresponding
author. E-mail: Edouard.perie@plantandfood.co.nz
Carbon sequestration in soil has the potential to counterbalance a significant proportion of life-cycle greenhouse
gas (GHG) emissions associated with (at least) some horticultural products, as well as improving soil
health and orchard productivity (Lal, 2010). Furthermore, potentially significant quantities of atmospheric
CO2 can also be stored in the standing biomass of perennial crops (Albrecht and Kandji, 2003).
However, the most widely used standard for GHG accounting, the PAS 2050 (BSI, 2011), currently does not
include above-ground biomass and changes in soil carbon stocks as a result of land use (unless provided for
in supplementary requirements). This is due to a lack of an agreed methodology, and uncertainty as to how to
measure these parameters and integrate them into a carbon footprint. Indeed, at the inventory phase, it is
difficult to measure accurately a change in the soil carbon stock over short time periods, whilst satisfying
statistical significance and power levels (Post et al., 2001) because of the spatial variability of carbon stocks
in soils and their small change with time. Measurement methods are costly and time consuming – and thus
not easily implementable. Regarding methodology, the grower’s potential to store carbon is site-dependent
due to the variability in the carbon storing capacity of different types of soil; arguably, this should be reflected
in a carbon footprint calculation. Furthermore the timeframe adopted for measurement of carbon
stock changes can have an important impact on the carbon footprint results (Milà i Canals et al., 2007), because
changes are often not linear over time. Lastly, maintenance of soil carbon is also important and it may
be desirable to account for this aspect. In this poster, we describe the challenges and the requirements for the
development of a reliable and practical methodology to measure soil and biogenic carbon stocks changes
over time in apple orchards, summarise methodological issues related to their integration into carbon footprint,
and discuss potential solutions.
References
Albrecht A, Kandji ST, 2003. Carbon sequestration in tropical agroforestry systems. Agriculture Ecosystems
& Environment 99(1-3):15-27.
BSI, 2011. PAS 2050:2011 Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of
Goods and Services. London, UK: British Standards Institute.
Lal R., 2010. Beyond Copenhagen: mitigating climate change and achieving food security through soil carbon
sequestration. Food Security 2(2):169-77.
Milà i Canals L., Romanyà J., Cowell SJ, 2007. Method for assessing impacts on life support functions
(LSF) related to the use of "fertile land" in Life Cycle Assessment (LCA). Journal of Cleaner Production
15:1426-1440.
Post WM, Izaurralde RC, Mann LK, Bliss N., 2001. Monitoring and verifying changes of organic carbon in
soil. Climatic Change 51(1):73-99.
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