Agriculture Reference
In-Depth Information
it uses no pesticides. In an attempt to understand
more fully the environmental impact of hemp
products, the hemp industry has undertaken a
life cycle analysis (LCA) of two products:
This project's objective was to promote the
development of a competitive, innovating and
long-lasting hemp fabric industry. This involved
the development of an improved production
chain to produce high-quality hemp fabric that
was ecologically sustainable. This was coupled
with an integrated quality control system for
the stems, fibres (crude and processed) and
thread founded on eco-label criteria. In order
to do this, the project had to evaluate the
environmental impact of the various products
used in the production of hemp textiles. It was
in this context that the impact of hemp pro-
duction in the field was studied by means of
an LCA.
The main impacts of hemp cultivation are
quantified and compared to those of other
annual crops. For hemp, the effects of modi-
fied farming practices and the amount of nitrate
lost through washing are explored.
•
a thermoplastic compound containing
hemp fibres;
the hemp cement used for cement walls
•
laid on a wooden frame.
The results of this analysis are presented in sec-
tion 21.3.
Hemp production does not result in sig-
nificant pollution. The study below presented
by Hayo van der Werf, although conducted in
Brittany, France, demonstrates this by compar-
ing hemp with a number of other important
European crops.
Here, once again, the environmental cre-
dentials of hemp are clearly demonstrated.
21.2 The Environmental Impact
of Hemp Cultivation
21.2.2
Materials and methods
21.2.1 Introduction
The environmental impact of eight annual
crops, including hemp, has been estimated by
an LCA, a method that allows the potential
impact of a product or function by quantifying
and evaluating the resources used and the envi-
ronmental emissions at each stage of the life
cycle: from the point at which those resources
are extracted through to the production of the
materials and the product itself, to the use of
the product and its ultimate disposal and recy-
cling (Guinée
et al
., 2002).
The environmental problems (or impact
categories) that will be considered need first to
be identified. In this study, we have considered:
eutrophication, climate change, acidification,
terrestrial pollution, energy use and the use of
cultivated land. Eutrophication includes all that
may result from the introduction of excessive
levels of nitrogen and phosphate fertilizers into
the environment. Climate change is defined as
the impact of emissions on the atmosphere's
ability to absorb radiated heat. Acidifying sub-
stances can have a wide range of effects on the
ground, water, living organisms, ecosystems
and buildings. Terrestrial pollution covers the
impact of toxic substances (in this study, this is
limited to heavy metal pollution) on terrestrial
Hemp demonstrates a number of agronomic
and environmental strengths. It covers the
ground quickly once it has emerged from the
earth and smothers the majority of weeds, thus
eliminating any requirement for herbicides. It
requires only a modest amount of nitrogen fer-
tilization, as its roots are very deep and are able
to use the mineralized nitrogen deposited in
the soil during the summer. In France, there
are no diseases capable of provoking signifi-
cant losses; as a result, there is no need for any
phytosanitary interventions during the growing
cycle (FNPC, 2002). Hemp is very resistant to
drought and, in practice, hemp cultivated for
straw does not need to be irrigated. Only those
crops cultivated for straw and seed are occa-
sionally irrigated. When harvested, hemp
leaves the ground clean, relatively dry and loos-
ened for some depth. It can therefore be said
that hemp is an excellent crop to follow and
can improve the yield of crops such as wheat
that are planted after it (FNPC, 2002; Gorchs
and Lloveras, 2003).
In 2002, the European Union financed a
study called HEMP-SYS (Amaducci, 2003).
