Agriculture Reference
In-Depth Information
identified for example based on a comparison of similar studies or expert estimation but in
this process it is always necessary to take into account the specifics of the particular situation.
If the process significance is set incorrectly, this could have a rough influence on the results of
the whole analysis.
Scheme 3.
Example of setting the boundaries of the system within LCA analysis [37]
To compare products (systems), it is necessary to define also the functional unit. The functional
unit is described as a quantified performance of a product system which serves as a reference
unit in a study of life cycle assessment [13]. It is an essential element which all study results
are related to. It must be chosen so as to be easily expressible and measurable. The functional
unit is the starting point for searching for alternative ways how to fulfil the function with a
lower negative impact on the environment [55]. [1] states that the determination of functional
units is as a crucial step especially when comparing systems with different levels of production
per hectare such as conventional and organic farming system. [15] recommends to involve
both functional units into calculations and perform the calculations for both the unit area and
the unit of production. The impact of organic system on the mitigation is usually measured
per unit area in order to enhance the objectivity. However, it is important to convert it also to
the production unit. Greenhouse gas emissions are lower in organic systems per unit area but
also per unit of production. However, environmental savings per unit area are due to lower
yields within organic farming roughly double as compared with the calculation per unit of
production [40]. [25] also states that due to lower yields within organic farming in the calcu‐
lation of GHG emissions per unit of production, the environmental load increases in relation
to conventional farming, so the resulting difference is less than when converted to the unit
area. This is consistent with findings of [36] who states that due to lower yields in organic
