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
53. A simplified tool for the estimation of N and P emissions due to the
use of fertiliser in a LCA study
Filippo Sessa 1,* , Massimo Marino 1 , Pierluigi Meriggi 2 , Matteo Ruggeri 3 , Michele Zerbini 4
1 Life Cycle Engineering, 2 Horta srl, 3 Univerisità Cattolica del Sacro Cuore, Piacenza, 4 Barilla G. R. Fratelli
S.p.a, Corresponding author. E-mail: sessa@studiolce.it
Emissions of nitrogen and phosphorus compounds from soil are among the most relevant sources of environmental
impact in the life cycle of most agricultural products. The most important emissions in air are
N2O, which has a high Global warming potential and NO and NH3 which contribute to acidification. The
most important emissions in water are nitrates and phosphates, which contribute to eutrophication of water.
Agricultural practices such as fertilisation and tillage could seriously affect these kinds of emission.
It is often difficult to estimate these emissions because they depend on a multitude of factors such as climate
conditions, soil characteristics and cultivated crops. There are models in literature that enable to estimate
them with a certain precision but in many cases they are too complicated and require input which would imply
money and time efforts that are not always available in a life cycle study. On the other hand it is possible
to estimate emissions using emission factors or equations which however are too simplistic and do not permit
for example to appreciate differences among different farming systems. The aim of this study was to identify
models that may be easy to handle and in the meanwhile enough accurate to take into account the main factors
that influence the emissions. This is important in particular when performing a Life Cycle Assessment
on a farm or on a territory level. With the individuated models a tool was then developed to permit the life
cycle analyst to get the values of emissions by inserting a few required inputs. Particular attention in the
choice of the models has been given to the responsiveness to different types and dosage of fertilisers.
The models individuated are Bouwman et al. (2002) for direct N2O emissions, IPCC (2006) for indirect N2O
emissions, Bouwman et al. (2002) for NH3 emissions from mineral fertilisers, Dohler et al. (2002) for NH3
emissions from organic fertilisers, Stehfest et al. (2006) for NO emissions, De Willigen (2000) for nitrates
emissions and Prahsun (2006) for phosphorus emissions.
Most of the input required can be obtained by asking the farmer and by soil analysis. Other data required are
the quantity of annual precipitation and the type of climate, which can be easily obtained from literature or
from some meteorological database. Some factors required by the models are taken from literature and provided
in the tool.
The result of the work was a tool that enables the life cycle analyst to easily get quite accurate estimates of
nitrogen and phosphorus emissions from agricultural soils. The development prospect for the tool could enrich
the internal database to make it more specific for determined crops or geographical areas.
References
Bouwman, A.F., Boumans, L.J.M., Batjes, N.H., 2002. Estimation of global NH3 volatilization loss from
synthetic fertilizers and animal manure applied to arable lands and grasslands. Global Biogechem. Cycles
16(2), 1024.
Bouwman, A.F., Boumans, L.J.M., Batjes, N.H., 2002. Modeling global annual N2O and NO emissions from
fertilized fields. Glob Biogeochem Cycles. 16(4), 1080-1107.
IPCC, 2006. Guidelines for National Greenhouse Gas Inventories
Prasuhn, V., 2006. Erfassung der PO4-Austräge für die Ökobilanzierung. SALCA-Phosphor. Zürich, CH,
Agrocope FAL Reckenholz.
Stehfest, E., Bouwman, L., 2006. N2O and NO emission from agricultural fields and soils under natural
vegetation: summarizing available measurement data and modelling of global annual emissions. Nutrient
Cycling in Agroecosystems. 74, 207-228.
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