Agriculture Reference
In-Depth Information
ment from the society in emergy terms (F), (2) Renewability (R/U), a mea-
sure of the share of the total emergy use that comes from local renewable
resources, and (3) Unit Emergy Value, UEV (U/output from system) [23].
1.3.2 LIFE CYCLE ASSESSMENT (LCA)
The LCA approach quantifies the environmental impacts associated with
a product, service or activity throughout its life cycle [24]. The method
looks at the impact of the whole system on the global environment by trac-
ing all material flows from their point of extraction from nature through
the technosphere and up to the moment of their release into the environ-
ment as emissions. LCA takes into account all direct and indirect man-
made inputs to the system and all outputs from the system and quantifies
the associated impacts on the environment.
Impact categories that are relevant and representative for the as-
sessment of agricultural systems [16] were considered: non-renewable
resource use as derived from fossil and nuclear resources [25], Global
Warming Potential over 100 years according to the IPCC method [26] and
a selection of other impacts from CML01 methods [27] and EDIP2003
[28], (i.e., eutrophication potential to aquatic and terrestrial ecosystems,
acidifi cation, terrestrial and aquatic ecotoxicity potentials, human toxicity
potential). In addition the use of fossil phosphorus was assessed.
The inventories for the LCA were constructed with the use of Swiss
Agricultural Life Cycle Assessment (SALCA) models [28], Simapro V
7.3.3 [29] and the Ecoinvent database v2.2 [30]. The following inputs and
emissions were based on other studies: life cycle inventory for vegetable
seedlings [31]; biomulch [32]; nitrous oxide and methane emissions from
open fi eld woodchip composting on the case study farm [33]. The Life
Cycle Inventory for irrigation pipeline from ecoinvent was adjusted to re-
fl ect the irrigation system of the case farm and the Swiss inventory for
irrigation was adjusted to refl ect the British electricity mix.
The analysis was carried out from cradle to the consumer's door with
respect to the ISO14040 [24] and ISO14044 [34] standards for environ-
mental Life Cycle Assessment. Upstream environmental impacts related
to the production of woodchips or manure were not considered. This is
