Agriculture Reference
In-Depth Information
Fig. 6.9.
Harvesting in the region of Toulouse by
the company, Chanvre de Garonne (Sébastien
Garcia ©, Trait d'Union Paysan, 2008).
Fig. 6.11.
Swathing the hurds with a giro swather
(ITC ©).
The introduction of turning equipment
and twin rotor swathers that deposit the hurds
centrally is being studied by the ITC in order to
improve yields and harvesting performance.
PRESSING
/
BALING
.
The choice of pressing into
round or square bales depends on the market
to be targeted (technical fibre or paper fibre)
and the design of the fibre extraction process.
In order to be transformed into paper pulp,
hemp hurds must be free of all plastic contami-
nation. When square bales are tied, however,
small pieces of twine are cut and mixed with
the hurds. Natural string made from sisal is not
elastic enough and breaks when the bale exits
from the compression canal. All the hemp pro-
duced by the LCDA and Interval/Eurochanvre
are pressed into round bales using equipment
with differing chambers (Fig. 6.12).
More recent productions, such as that of
Euralis/Agrofibre in the region of Toulouse and
that of the CAVAC in the Vendée, have chosen
to press hemp into bales for transport and stor-
age reasons. For this sort of storage, the cutting
of hurds into short pieces is a prerequisite.
Fig. 6.10.
Combine harvester BAFA (ITC ©).
extraction company, BAFA (Fig. 6.10). It allows
hemp seed to be harvested, the hurds to be cut
into pieces of equal length (approximately 50 cm)
and its organization into swaths in one passage.
This means of harvesting allows the hurds to
be pressed into bales and has a processing rate
of 1.3 ha/h.
Given that the material transits through
the machinery, problems can occur in fields
where the yield approaches 10 t of DM/ha. In
such cases, the processing rate is lower.
SWATHING
.
This procedure is performed
almost exclusively by mono-rotary swathers
(Fig. 6.11). In addition to collecting the hurds
before compressing them, swathing softens
the hurds, thereby facilitating drying and
retting. According to the weather conditions
and the crop yield, two or three passages may
be realized.
6.2.4 Yields
Depending on the objectives specified, yields will
vary. A number of constants exist, however.
As mentioned earlier, yield is virtually
independent of the sowing density across a
range starting at 40 plants/m
2
, with an increase
