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

PARALLEL SESSION 6B: FISHIERIES, SOIL, AND EMERGY METHODS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Regionalised method to assess soil erosion in LCA
Montse Núñez 1,2,* , Assumpció Antón 1,3 , Pere Muñoz 1 , Joan Rieradevall 4
1 IRTA, Sostenipra. Centre de Cabrils 08348 Cabrils, Barcelona, Spain
2 INRA-LBE, Avenue des Etangs 11000 Narbonne, France
3 Departament d’Enginyeria Química, Universitat Rovira i Virgili 43003 Tarragona, Spain
4 ICTA, Sostenipra. Universitat Autònoma de Barcelona 08193, Bellaterra, Barcelona, Spain
Corresponding author. E-mail: montse.nunez@supagro.inra.fr
ABSTRACT
One of the most relevant and endangered ecosystem services worldwide due to land use change and inappropriate land use practices
is the capacity of ecosystems to stabilize soils by preventing soil erosion. This research was meant to develop a method to include the
assessment of soil erosion in LCA on a global scale. The method deals with land occupation impacts. As soil erosion depends on
local conditions, characterisation factors were regionalised on a 5 arc-minutes grid-cell level resolution. Two endpoint indicators
covering the areas of protection damage to resources and damage to ecosystem quality were proposed. The method was applied to the
agricultural stage of five agricultural crop rotations. Further research efforts should aim at applying the method beyond the agricultural
stage and to identify a feasible and relevant spatial scale at which to aggregate characterisation factors to cope with data gaps on
location of processes.
Keywords: ecosystem services, land use, soil erosion, spatial differentiation, USLE
1. Introduction
Ecosystem services (ES) are resources and processes that are supplied by natural ecosystems. Despite
their fundamental role in sustaining ecosystem functioning and human activities, they have been traditionally
disregarded in life cycle oriented methods such as life cycle assessment (LCA), a method that is meant to
encourage environmental sustainability. This oversight can lead to improper decisions. One of the most relevant
and endangered ES worldwide due to land use change and unsustainable land use management practices
is the capacity of ecosystems to stabilise soils and to prevent soil sediment accumulation downstream. Soil
erosion leads to a reduction of soil quality, as usually a large amount of nutrients is lost together with the
topsoil. Nutrient impoverished soils are less capable to provide ecosystem services. Detached soil nutrients,
such as phosphorous, organic matter and heavy metals lead to pollution of water courses and lost particles to
contamination of the air. Annually, humans cause de loss of 50 to 75 billion metrics of soil (Harvey and Pimentel,
1996). Agricultural lands account for 75% of the soil erosion worldwide, though it also occurs in
other human-modified ecosystems, such as during the construction of roads and buildings. Several methods
deal with the issue of erosion in LCA. Cowell and Clift (2000) proposed a non-spatially-explicit indicator,
thus one generic characterisation factor (CF), for assessment of soil depletion, the static reserve life (years).
The LANCA® calculation tool (Beck et al., 2010), based on Baitz (2002)’s method, allows assessing soil
loss for specific cases of land use that can be used within life cycle inventory (LCI) databases. Saad et al.,
(2011) adopted the LANCA® modelling approach to derive CFs of land occupation and land transformation
for Canada at different spatial scales. Van Zelm et al., (2011) proposed CFs for erosion due to agricultural
land occupation for the world at the country level. The methods by Saad et al., (2011) and Van Zelm et al.,
(2011) are spatially-resolved, that is, CFs include site-specific geospatial information, because land use impacts
are highly influenced by local conditions regarding climate, soil properties and landscape. So far, even
though some proposals already exist for LCA to integrate soil erosion, approaches are still in its infancy and
the discussion on its characterisation is far from being settled.
The objective of this research was to go one step further towards the integration of ES in LCA by developing
a regionalised method for the world to include land occupation impacts of any type of human activity
on the erosion regulation ES. To show the applicability of the method, erosion and environmental impacts
from growing agricultural rotations with food and energy crops in Spain were assessed.
2. Method
Two endpoint indicators covering the areas of protection (AoP) damage to resources and damage to ecosystem
quality were defined. CFs for the two modelled impact pathways were regionalised on a 5 arcminutes
(approximately 10*10 km 2 ) resolution grid, without further aggregation on broader scales.
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