Agriculture Reference
In-Depth Information
Sustainable Development
Pierre Bouloc
1
and Hayo M.G. van der Werf
2
1
La Chanvriere de L' Aube (LCDA), France;
2
INRA, Rennes, France
21.1 Introduction
the amount that has a life expectancy in excess
of the annual life cycle, we have taken into
consideration only the straw destined for use in
products with a long life expectancy. The hemp
seed, roots and leaves are therefore not
considered.
As a result, hemp straw produced by 1 ha
of land can stock approximately 3.06 t of
carbon.
1
Carbon is stored for a long time where the
derivatives of straw are used in a perennial
way, that is to say, where the straw is used to
produce materials with a long life expectancy.
The modern uses to which hemp straw
and its derivatives are put do precisely that,
and thus fix carbon for long periods. For
example:
This final chapter opens up new perspectives
and possibilities for hemp. At a time when
humans are worrying about their future and
questioning the impact their behaviour has on
the environment, it is reassuring to note that a
number of solutions are presenting themselves
which have the potential to address these
concerns.
Recent studies, building on those under-
taken at the end of the 1990s, have demon-
strated that hemp has the potential to make an
important contribution to the protection of the
environment and, in particular, the campaign
against the greenhouse effect.
The following serve as reminders of some
of the facts presented in this topic:
•
Hemp wool has a life expectancy of 20
years.
Panels made from hemp fibre used in the
•
1 ha of hemp can produce nearly 12 t of
•
dry matter (DM)/year, with a humidity
level of 15%.
Exported straw: about 8 t (or 6.8 t of
manufacture of car doors will last, on aver-
age, for 7 years.
Hemp cement lasts for over 30 years.
•
•
DM).
Hemp seed: 1.2 t (or 1.2 t of DM).
•
Plastics made using hemp fibre can be
•
expected to last, on average, for 7 years, etc.
•
Root system and leaves: over 3.5 t (or 3.5
t of DM).
It is clear from this that the use of hemp (and
natural fibres in general) in long-lived materials
can contribute to a reduction in the greenhouse
effect.
Hemp is also a crop that demonstrates its
environmental credentials during cultivation, for
NB Hemp contains approximately 45% of the
atmospheric carbon taken up during photosyn-
thesis.
Considering that calculations of the
amount of carbon stored must take into account
