Agriculture Reference
In-Depth Information
following a cut-off approach that makes a clear division between the sys-
tem that produces a by-product or waste and the system using it. The emis-
sions from livestock farming (associated with the production of manure
used in the models of standard practice) are fully assigned to the livestock
farmer and the gardener is responsible for the production of woodchips.
However, environmental impacts from the transport of both type of inputs
to the farm, their storage and composting at the farm and all the emissions
to soil, air and water that arise from their application were considered in
this study. The results of the impact category non-renewable resource use
were investigated in more detail by looking at the relative contribution of
particular processes to the overall resource use, because of some similari-
ties with the emergy assessment.
1.4 MODELS FOR STANDARD PRACTICE OF VEGETABLE SUPPLY
SYSTEM
The overall aim of developing these models is to assess the resource use
and environmental impacts of providing the same service as the case
system but in the dominating supermarket based system. The two model
systems, M-Low and M-High, express the range of standard practice for
organic vegetable production as defined from the Organic Farm Manage-
ment Handbook [35]. Since the information in this handbook is indepen-
dent of scale, i.e., all numbers are given per ha or per kg, then the model
systems are also independent of scale. Both model systems provide veg-
etables in the same quantity at the consumer's door (in food energy) and
of comparable quality as the case study. The mix of vegetables provided
is identical to the case system for the eight crops (two types of potatoes,
carrots, parsnips, beetroots, onions, leeks and squash) constituting 75% of
the food energy provided (Table 1). For the remaining 25% representing
40 crops at the case farm, four crops (white cabbage, cauliflower, zucchini
and lettuce) have been chosen based on the assumption that they provide a
similar utility for the consumer.