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
528
The effect of crop management on soil organic matter in the carbon
footprint of agricultural products
Simona Bosco * , Claudia Di Bene, Enrico Bonari
Institute of Life Sciences – Scuola Superiore S. Anna, Piazza Martiri della Libertà, 33 - 56127 Pisa, Italy
Corresponding author. E-mail: s.bosco@sssup.it
ABSTRACT
The agricultural sector has an important role in greenhouse gas (GHG) mitigation, since cropland soils can also act as sinks. Attention
has already been drawn to the value of soil quality and soil organic matter (SOM) in the life-cycle of agricultural products. Nevertheless,
many life-cycle assessment studies of food and non-food products do not take into account changes in SOM in arable land.
A simpler one-compartment SOM model is needed to be integrated into the LCA study. Recently, many authors have adopted the
Hénin-Dupuis SOM model for cropping system and orchard studies under different climate conditions, and it has proved useful for
less-detailed modelling at sites where input requirements for running the more complex models are not readily available. The model
was applied to wine production considering four scenarios with decreasing levels of OM inputs. This SOM balance method was
sensitive to changes in management practices.
Keywords: crop management, Hénin-Dupuis model, soil organic matter, organic matter input, tillage intensity.
1. Introduction
The role of agriculture in climate mitigation centres on a conservative soil management designed to both
protect soil quality and guarantee GHG emissions reduction (Smith et al., 2008). It is well-established that
deep tillage, over-fertilisation, excessive use of pesticides and irrigation, and the removal of crop residues
can dramatically affect soil quality (Lal 2004).
As Nemecek and Erzinger (2005) have indicated, farms are characterised by high variability in both natural
and management factors, and by difficult-to-measure emissions. Attention has already been drawn to the
crucial role of soil quality and soil organic matter (SOM) in the life-cycle of agricultural products (Cowell
and Clift 1997, 2000; Milà i Canals et al., 2007 ). Nevertheless, many life-cycle assessment studies of food
and non-food products do not take into account changes in SOM in arable cropland (Brentrup et al., 2004;
Milà i Canals et al., 2006; Mourad et al., 2006; Hillier et al., 2009; Roy et al., 2009; Gazulla et al., 2010;
Muñoz et al., 2010; Bosco et al., 2011). This remains something of an unresolved issue in LCA, due to the
spatial and temporal variations, and local environmental uniqueness of soil quality (Reap et al., 2008). Neither
PAS2050 or GHG Protocol Standard consider until today soil emissions except in instances of land-use
changes (BSI, 2011; WRI/WBCSD, 2004). To date, few studies have incorporated soil into an LCA study
(Beck et al., 2010; Mila i Canals et al., 2007; Meisterling et al., 2009; Brandão et al., 2011; Nemecek et al.,
2011; Ponsioen and Blonk 2011; Saad et al., 2011) and no common methodology for its estimation and LCA
inclusion exists.
Soil quality and SOM changes are entirely site-specific, as they are strongly influenced by management
practices and soil and climate conditions. Many process-oriented SOM models are available for charting its
evolution on a daily, monthly or annual basis and they have already been incorporated into LCA analyses
(Milà i Canals et al., 2007; Hillier et al., 2009). However, the huge amount of data required (meteorological
data, crop phenological data, and chemical and physical soil characteristics) to run these models and to establish
the life cycle inventory (LCI) could limit widespread use of this approach.
A simpler one-compartment SOM model would be more easily integrated into the LCA study. Recently,
many authors have adopted the Hénin-Dupuis SOM model for cropping system and orchard studies under
different climate conditions, and it has proved useful for less-detailed modelling at sites where input requirements
for running the more complex models are not readily available (Sofo et al., 2005; Bayer et al.,
2006; Bockstaller et al., 2008; Bechini et al., 2011; Di Bene et al., 2011).
In this paper we proposed a new method for soil inclusion in agriculture LCA, integrating the Hénin-
Dupuis SOM model into a carbon footprint (CF) analysis. Sample results were reported in a case study on
wine to test the impact of different management practices on the overall result. Wine was chosen as a case
study because it is a widely-studied food product and because of its importance within international and Italian
food markets.