Page 63 - Materials Chemistry, Second Edition

The Application of Life Cycle Assessment on Agricultural 49

combustion (Quintero et al. 2008). Another well-known example is the digestate, a
residue of anaerobic digestion, which can be used as a substitute of mineral fer-
tilizers (Lukehurst et al. 2010; Korres et al. 2011; Taylor et al. 2012; Chambers
and Taylor 2013).
It is worth mentioning that some of the inputs and related environmental effects
throughout the biofuel production chain may be indirect such as the energy and
related emissions from the manufacture of feedstock production inputs, e.g., fer-
tilizers, herbicides, lime or from the pre-treatment of the feedstock (e.g., macer-
ating) or other activities, e.g., mixing and water-pumping activities in anaerobic
digestion plant (Korres et al. 2011; Korres 2013). It is also vital to note—and to
reflect in biofuel analyses—that the indirect impacts of biofuel production and in
particular the destruction of natural habitats (e.g., rainforests, savannah, or in some
cases, the exploitation of ‘‘marginal’’ lands which are in active use, even at
reduced productivity, by a range of communities, often poorer households and
individuals) to expand agricultural land, may have larger environmental impacts
than the direct effects. The indirect GHG emissions of biofuels produced from
productive land that could otherwise support food production (reference system for
comparisons) may be larger than the emissions from an equal amount of fossil
fuels (Delucchi 2006; Farrell et al. 2006). Attention to these issues is vital if
biofuels are to become a significant component of sustainable energy and socio-
economic systems (Kammen et al. 2007).
In addition, biofuel production and usage also displaces some environmental
effects because they substitute in fuel and other markets for products that have
their own environmental effects. The extent to which the coproducts of biofuel
production displace other products and their environmental impacts (rather than
stimulate additional consumption) depends on the elasticity of demand in the
relevant markets (the more inelastic the demand, the greater the displacement), the
way in which the coproducts affect supply curves, and other market and non-
market (i.e., political and regulatory) factors (Kammen et al. 2007).

4.2 LCA and Agricultural Production

Concerns about the environmental impacts of agricultural production systems and
energy sectors have led to considerable publicity about the importance of applying
LCA technique for minimizing these burdens. LCA has been promoted as one of
the best ways of determining the real impacts of agricultural products (Loerincik
et al. 2008; Harris and Narayanaswamy 2009) and consequently has been proved
an important tool for possible mitigation options and eco-friendly production. The
application of mineral and organic fertilizers, soil management practices, animal
production systems, and manure management (Mummey et al. 1998; Steinfeld
et al. 2006; Smith et al. 2007) are some factors which enhance the environmental
burden of agricultural production including GHG emission, eutrophication, acid-
ification, among others.