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
119. Designing sustainable crop rotations using life cycle assessment of
crop sequences
Frank Hayer 1 , Emmanuelle Bonnin 2 , Benoit Carrouée 3 , Gérard Gaillard 1 , Thomas Nemecek 1, , Anne
Schneider 3 , and Christophe Vivier 4
1 Agroscope Reckenholz-Tänikon Research Station ART, CH-8046 Zurich, Switzerland, 2 Chambre d'Agriculture
de la Nièvre, F-58028 Nevers, France, 3 Union Nationale des Plantes Riches en Protéines UNIP, F-
75008 Paris, France, 4 Chambre d'Agriculture de l'Yonne, F-89015 Auxerre, France, Corresponding author.
E-mail: thomas.nemecek@art.admin.ch
The project CAS DAR PCB (Amélioration des performances économiques et environnementales de
systèmes de culture avec Pois, Colza et Blé) aimed at analysing and optimising crop rotations in three French
regions by the selection of crops in a crop rotation, defining their sequence and by different nitrogen fertilisation
levels. An LCA study of a large number of crop rotations is very time consuming. Therefore the different
sequences of previous crop-main crop were defined and analysed by LCA, considering the effects of a
specific previous crop on cultivation, fertilisation, yield and emissions of the main crop. These crop sequences
were subsequently combined to analyse 58 crop rotations. Two functional units were used in this
analysis: hectare per year and € gross margin II. The study focused on the effect of legumes and reduced N
fertilisation on environmental impacts.
Production data were collected by the Chambers of Agriculture for a typical cultivation in Burgundy,
Beauce, and Moselle for the reference period 2002-2008. The yield data were taken from survey of field
level by the Chambers of Agriculture. Background data describing infrastructure, inputs and processes
stemmed from the ecoinvent database version 2.01 (ecoinvent Centre, 2007). The direct field emissions
(NH3, N2O, P, NO 3- , heavy metals and pesticides) were estimated by models described in the SALCA
method (Nemecek et al., 2010). The analysis included the production from cultivation up to the delivery at
farm gate, as well as the environmental impacts linked with input factors and the direct field emissions. The
selected rotations are given in Table 1. The gross margin II was calculated based on mean prices in the reference
period.
To illustrate the results the global warming potential (GWP) is shown for selection crop rotations in Fig. 1.
Following Nemecek et al. (2008) a difference of 4% between two crop rotations can be considered as significant.
The same tendencies were found across all impact categories. The alternative crop rotations with pea
(P1 to P3) consistently reduced the GWP as compared to the standard rotations without pea (S1 and S2), both
per hectare and year and per € gross margin II. The effect was similar whether barley in the standard rotation
was replaced by pea (P1) or pea was added (P2 and P3). The global warming potential per ha and year was
reduced by around 10% and per € gross margin by around 12%. In P2 pea is inserted before the stubble
wheat in rotation S2. This reduced the GWP by around 14% per ha and year and 19% per € gross margin II
compared to S2. Looking at the second option, the reduced fertilisation, comparing the conventional and
integrated rotations in Beauce shows that the impact per ha is reduced, whereas the impact per € gross margin
II remains constant due to lower revenues. Combining introduction of pea with reduced N fertilisation
(Beauce_Int P1-P3) seems to be the most effective way to reduce the GWP.
The analysis illustrates that peas allow to decrease impacts per ha and year on a rotational level and to increase
the eco-efficiency (lower impacts per € gross margin II). This is caused by positive rotational effects
(e.g. higher yields or a lower fertilisation in succeeding crops). Therefore this strategy is favourable compared
to a reduced fertilisation in single crops. Combining both measures is the most effective strategy when
looking at impacts, but on the other hand the gross margin II is reduced by around 40 € compared to the
standard rotations.
References
ecoinvent Centre (2007): ecoinvent Data - The Life Cycle Inventory Data. Swiss Centre for Life Cycle Inventories,
Dübendorf, ISBN 3-905594-38-2 available at http://www.ecoinvent.org.
Nemecek, T., Freiermuth Knuchel, R., Alig, M. & Gaillard, G. (2010): The advantages of generic LCA tools
for agriculture: examples SALCAcrop and SALCAfarm. In: 7th Int. Conf. on LCA in the Agri-Food Sector,
Notarnicola, B. (eds.). Bari, Italy. 433-438.
Nemecek, T., von Richthofen, J.-S., Dubois, G., Casta, P., Charles, R. & Pahl, H. (2008): Environmental
impacts of introducing grain legumes into European crop rotations. European Journal of Agronomy, 28:
380-393.
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