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

GROUP 4, SESSION B: CROP PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
118. Allocating environmental burdens from fertilisation to crops in a
rotation
Alice Gueudet 1,* , Hervé Bossuat 1 , Marilys Pradel 2 , Afsaneh Lellahi 3 , Aurélie Tailleur 3
1 ACTA, le réseau des instituts des filières animales et végétales, 149 rue de Bercy – Paris, F-75595, France,
2 Irstea, UR TSCF Technologies et systèmes d'information pour les agrosystèmes, Domaine des Palaquins –
Montoldre, F-03150, France, 3 ARVALIS-Institut du végétal, Service Agronomie Economie Environnement,
Boigneville, F-91720, France, Corresponding author. E-mail: alice.gueudet@acta.asso.fr
Allocation is a complex issue for LCA practitioners. Due to many allocation methods, the choice between
them can have a significant impact on the results. It is particularly relevant when applying LCA to assess
fertilisation impacts as all nutrients brought by fertilisers are not all taken up by the crop in the system under
study but remain available for future crops in rotation. Crop residues also produce nutrients which return to
soil after harvest. Hence, these nutrients can be considered as co-products from the crop.
Fertilisation contributes highly to different potential impacts for crops: it induces in particular 30-60% of the
primary energy consumption, 60-80% of the global warming potential, 90% of the eutrophication potential,
80-90% of the acidification potential (personal communication from ARVALIS and UNIP). Thus, allocation
method used to allocate fertilisers to crops can be decisive for the LCA outcomes.
Allocating burdens from fertilisation is a subject of concern since the beginning of agricultural LCA and
different reports dealt with this issue (Audsley et al. 2003; Gac et al., 2006). Recently, a working group (Agri
Footprint Method, Blonk 2010) made recommendations to take into account mineral and organic nutrients
from synthetic fertilisers, manure and crop residues. However, these references rarely lead to common accepted
rules in term of methodology or their suggestions are not always easy to apply because of data availability.
In the framework of a project aiming at assessing environmental impacts of crop fertilisation by LCA, a bibliography
review has been conducted to identify the different solutions involved in LCA literature regarding
allocation rules for PK nutrients in synthetic fertilisers, N from manure and N from crop residues (Table 1).
Considering this large range of choices, allocation rules have been selected in order to be tested on study
cases which will simulate levers to reduce impacts from fertilisation such as cover crops introduction and the
use of different types of fertilisers (mineral and organic). These simulations will assess the rules feasibility
and identify the most consistent. This work will result in recommendations about cropping plan allocation
for mineral and organic N, P, K nutrients and for crop residues, regarding the aim of the study and the data
availability.
References
Audsley et al. 2003, Harmonisation of environmental life cycle assessment for agriculture, final report DG
VI Agriculture 2003, 101p.
Blonk et al. 2010, Methodology for assessing carbon footprints of horticultural products - A study of methodological
issues and solutions for the development of the Dutch carbon footprint protocol for horticultural
products Blonk Milieu Advies p.36-40
European Commission 2010, ILCD Handbook, General Guide for Life Cycle Assessment – detailed guidance,
394p.
Gac et al. 2006, GES’TIM Guide méthodologique pour l’estimation des impacts des activités agricoles sur
l’effet de serre, Version 1.2, 156p.
William et al. 2006, Determining the environmental burdens and resource use in the production of agricultural
and horticultural commodities. Defra project report IS0205, 97p.
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