Agriculture Reference
In-Depth Information
products; then there is a thermoplastic part
and a cement part.
the material is used to produce, its use, its
potential for recycling and what happens to it
at the end of its life cycle.
The results also demonstrate some unfa-
vourable potential impacts when compared
with other agroindustrial activities. Nitrogen
fertilization plays an important role in the envi-
ronmental impact of hemp fibre and hemp
straw. It is associated principally with the pro-
duction of greenhouse gases (production of
mineral fertilizers and transformation into ferti-
lizers in the ground), the consumption of non-
renewable energy resources and pollution of
waterways with nitrates. Parameter tests
applied to this stage have also shown that a
reduction of 20% in the nitrogen dose can
result in a reduction in potential impacts of the
order of 10% (assuming a similar yield). Not
included in this calculation are the production
of waste, destruction of the ozone layer and
pollution of water.
Looking beyond the LCA results, hemp
cultivation necessitates only a limited amount
of nitrogen fertilization and does not require
phytosanitary products or irrigation. It can be
compared favourably with other major crops,
as shown in the preceding section.
The agronomic study
WHICH SYSTEM IS TO BE STUDIED ? . The system
studied in this part consists of the agricultural
production (termed technical itinerary) and the
production of the hemp fibres and hemp straw
(termed primary transformation). The func-
tional unit used is the kilogramme.
The system studied has not taken into
account the seed production or the production
of hemp seed that is sometimes associated with
straw production. It has not considered either
inputs with a weight less than 2% of the total
mass of inputs (NF P01-010). The dust pro-
duced by the primary transformation proc-
ess is considered a waste product (Chapters
11-18 on the uses of hemp). Finally, the repar-
tition of the potential environmental impacts of
hemp straw between fibre and straw was
undertaken in bulk (60% hemp straw, 40%
fibre) and in value (68% fibre and 32% straw).
ANALYSIS OF THE INVENTORY . In applying the ISO
14040 standard, the value of the inputs and
transport distances attributed to the production
of hemp straw was calculated using values sup-
plied by the members of the partners (FNPC,
LCDA, Eurochanvre and PDM Industry).
The value of the outputs attributed to
straw production was calculated using formu-
lae derived from the bibliography.
Carbon storage in the product, arising as
a result of photosynthesis, has been taken into
account in this study.
Thermoplastics
LIMITATIONS OF THE STUDIES UNDERTAKEN . The
compound studied here is a mix of polypropyl-
ene and hemp fibres. The proportion by mass
of these two ingredients is 70% polypropyl-
ene:30% fibre. The functional unit used is the
kilogramme.
The study covers the production and trans-
portation of the primary materials, together
with the compounding phase. The compound
thus produced is stored in bulk ready for use.
Inputs of less than 2% of the total mass of
inputs have not been included in the calcula-
tions (NF P01-010).
EVALUATION OF THE IMPACT AND INTERPRETATION OF
THE LIFE CYCLE . The results show a favourable
impact with regard to the greenhouse effect. In
fact, the potential value of this impact is
between -1.7 (allocation by mass) and -2.9
(economic allocation) kg CO 2 eq/kg of fibre
and between -1 (economic allocation) and -1.9
(allocation by mass) kg CO 2 eq/kg of hemp
straw. The inclusion of carbon storage in the
fibre and hemp straw arising through photo-
synthesis explains the positive result obtained
for the agronomic part. The duration of carbon
storage depends on the type of end product
ANALYSIS OF THE INVENTORY . The transport dis-
tances for the primary materials and the quan-
tity of the inputs (materials and energy) used in
the reference scenario described below have
been provided by AFT Plasturgie.
The analysis of the inventory for hemp
fibre is presented above. The analysis of
 
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