Agriculture Reference
In-Depth Information
The sustainability aspects of resource use and environmental impacts
of food supply systems can be assessed by Life Cycle Assessment (LCA)
[16,17] or emergy assessment [18,19]. Emergy accounting and LCA are
largely based on the same type of inventory (i.e., accounting for energy and
material fl ows) but apply different theories of values and system bound-
aries [20]. In emergy accounting, all fl ows of energy and materials are
added based on the total available energy (exergy) directly and indirectly
required to produce the fl ow. Emergy accounting is particularly suited for
assessing agricultural systems since the method accounts for use of freely
available natural resources (sun, rain, wind and geothermal heat) as well
as purchased resources from the society [18]. LCA draws system bound-
aries around human dominated processes (resource extraction, refi ning,
transportation, etc.) and includes indirect resources used throughout the
supply chain, such as the transport of inputs supplied into the production
system. Unlike emergy accounting, LCA disregards energy used by nature
and normally also labor. LCA on the other hand considers emissions to the
environment in addition to resource use. Due to the differences in system
boundaries and scope of analysis, emergy and LCA are complementary
methods [21].
We studied the sustainability of a small-scale low-input organic veg-
etable food supply system by evaluating empirical data on resource use
and emissions resulting from production and distribution of vegetables in
a box-scheme. This specifi c case was chosen because the farm is managed
with a strong preference to increase crop diversity and to close the produc-
tion system with regard to external inputs. Combined with the box-scheme
distribution system it thus represents a fundamentally different way of
producing and distributing food compared to the dominating supermarket
based systems. Our hypothesis was that the food supply system of the case
study uses fewer resources (especially fewer non-renewable resources)
when compared to standard practices. To test this we developed two or-
ganic vegetable food supply model systems, low and high yielding. Each
system provided the same amount of food as the case study system, and
the food produced was distributed via supermarkets rather than through a
box-scheme. The case supply system is benchmarked against these model
systems based on a combined emergy and LCA evaluation. Therefore,
within this study we aimed to evaluate whether it is possible to perform
