30 and 31 July 1992

H.M.G. van der Werf

Agricultural University, Dept. of Agronomy, Wageningen.
Research Station for Arable Farming and Field Production of Vegetables,
Centre for Agrobiological Research (CABO-DLO).
P. O. Box 14, 6700 AA Wageningen, The Netherlands


In the Netherlands a comprehensive study investigating the feasibility of
fibre hemp as a new arable crop and as a raw material for the paper
industry is currently under way. Breeding and agronomy researchers
involved in this programme have visited and established links with
colleagues in Hungary (De Meijer et al., 1990), Ukraine (Hennink et al.,
1991) and Poland (Hennink, CPRO-DLO, personal communication 1992). In
these countries hemp is used for textile and cordage production.
In France hemp is used for paper production. This report presents the
results of a short visit to the National Federation of Hemp Producers at Le
I wish to express my gratitude to Mr. Mathieu and Mr. Beherec for their
hospitality and readyness to answer my questions. E.P.M. de Meijer has
been of great help in the writing of the section on hemp breeding in this

Hayo vander Werf
Wageningen, November 2992


At Le Mans three organisations are involved with hemp.
The Federation Nationale des Producteurs de Chanvre (FNPC) conducts
research concerning the agronomy and processing of hemp and breeds new hemp

The Comite Economique Agricole de la Production du Chanvre (CEAPC)
organises the production contracts between hemp growers and hemp buyers and
markets the seed.

The Cooperative Centrale des Producteurs de Semences de Chanvre (CCPSC)
contracts growers for hemp seed production, buys the seed and markets it.

Mr. Jean-Paul Mathieu is the director of each of the three organisations.
On my visit to Le Mans I spoke with him and with Mr. Olivier Beherec, the
hemp breeder.
Address: 30 Rue Paul Ligneul, P.O. Box 119, 72003 Le Mans CEDEX, France,
Tel 43289923 Fax 43770916


In 1992 3,950 hectares (ha) of hemp is grown in France, of this surface,
370 ha was for the production of seed for sowing. About 2650 ha is grown
in the region of Troyes (eastern France). 1250 ha of hemp is grown in the
region of Le Mans (western France), 50 ha is grown in the Southwest of
France. In 1992 200 ha of hemp is grown for the production of high quality
seed for sowing, on another 170 ha second quality sowing seed is produced.
This seed is cheaper but will produce a crop containing about 70%
monoecious plants and 30% male plants, whereas hemp grown from high quality
seed will contain very few male plants and will consist almost exclusively
of monoecious plants.


The FNPC has bred a number of monoecious hemp varieties. Fibrimon 21,
Fibrimon 24 and Fibrimon 56 were bred in France in the nineteen-fifties by
crossing the same parental populations as described for this purpose by
Bredemann et al. (1961). The number added to the names of the French
cultivars indicate lateness, the higher the number, the later the cultivar.

In 1965 a collection of 100 fibre hemp accessions was evaluated for stem
quality, productivity and also for future availability. The original
intention of this screening was to select optimal parents for the
production of hybrid F1 cultivars (heterosis breeding) without domestic
maintenance of the parents. Out of these 100 accesions 30 were retained
and crossed with Fibrimon. At a later stage the idea of heterosis breeding
was left and the best performing hybrids were backcrossed with Fibrimon and
stabilised to new true breeding monoecious cultivars. Three of these
cultivars are presently commercialised as a replacement for the Fibrimon
cultivars. These cultivars are Fedora 19, Felina 34 and Fedrina 74, the
dioecious parents used in making these cultivars were respectively JUS-9,
Kompolti and Fibridia. Another more recent cultivar is Ferimon 12, which
is an early maturing selection from Fibrimon 21, Cultivar Futura 77 is
derived from the same hybrid offspring as Fedrina 74 but it was selected
for a somewhat later date of flowering.

In recent years the breeding programme has focussed on reduction of the THC
content. All varieties have less than 0.3% THC in the inflorescence,
meeting the EEC requirement. All varieties exist in two THC levels:
between 0.3 and 0.1% and below 0.1%. The two versions are strictly similar
except for the THC content. For example Fedrina 74 exists in a version
containing 0.20% THC and another version containing 0.07% THC. For some
varieties, the low-THC version is not available for sale. The seed of the
varieties containing less than 0.1% THC are sold only in France. Varieties
containing no THC (0.001%) have been obtained by crossing existing
varieties with a special variety containing an "anti-THC gene". Agronomic
characteristics of these varieties are still inferior to those of the THC
containing varieties. Mr. Mathieu thinks that this can be overcome and
expects that THC-free varieties with good agronomic characteristics will be


In the rotation hemp is an easy crop: it does not require any pesticides
apart from a seed dressing, it suffocates weeds and leaves a good soil
structure. Furthermore it can be grown during 2 or 3 consecutive years in
the same field.
Hemp will perform well on many types of soil, as long as the pH is not
below 5. Crop growth can be very much impaired by water logging and by
compaction of the tilled layer. Crusting soils may cause problems as the
emergence is easily hampered by a crust.
A crop yielding 8 tons / hectare of stems (at 16% humidity) will contain
65 to 80 kg of Nitrogen (N), 20 kg of Phosphorus (P), and 120 kg of
Potassium (K). Recommended fertilizer gifts (depending on fertility
status of the soil) are: 100 to 140 kg of N / ha, 80 to 120 kg of P / ha
and 160 to 200 kg of K / ha. Too much N may cause lodging.


Hemp is sown in the second half of April or in the beginning of May.
Earlier sowing increases risks linked with slower germination such as poor
emergence due to a crusting soil or more severe competition from weeds.
About 400 seeds / square meter is desirable for several reasons. The
higher the plant density, the shorter the crop. In order to be able to
harvest the crop using machines which are currently used in other crops,
the height of the crop should not exceed 2.5 metres. Otherwise problems
may arise with the use of the mower-conditioner, a machine which breaks the
green stems so that they dry more rapidly. The mower-conditioner does not
work well with the thicker stems which are obtained from hemp grown at a
low plant density.

Furthermore, at a high plant density the proportion of bark in the stem is
high and in the processing factory the bark separates more easily from the
wood in fine stems such as are obtained at high plant densities. When hemp
is grown for the production of seed for sowing the plant density is 10 to
20 plants per square meter.


Currently no harvesting equipment specially designed for hemp is in use in
France. In the past a special machine (a "pick-up egreneur") was used
after the hemp had been mown and dried to pick up the stems and separate
the grain from the stems. These machines have been largely abandoned as
they were expensive due to their low capacity (30 ha per harvest season).
The pick-up egreneur is used only for hemp grown for the production of
sowing seed now. In 1986 a machine which separates hemp stems into wood
and bark in the fied was developed. The prototype did perform
satisfactorily from the technical point of view, but it was too expensive,
so this technology has not been a success. Currently two harvest methods
are used for fibre hemp. Both methods only involve machines which are used
in other crops as well.
a) The crop is mown at the beginning of September using a cutter
bar or a mower-conditioner. The mower-conditioner is used most frequently,
the distance between the crushing rolls is kept relatively large, in order
to limit losses of grain. The hemp is laid down in a swath and will take
about 4 days (mower-conditioner) or about 8 days (cutting bar) to dry
(14 to 18% humidity in the straw). Once the hemp is dry it will be baled.
The grain is separated from the stems in the proessing factory.
b) Around the 15th of September a combine harvester set at 1.50
metres mowing height cuts off the tops of the plants and threshes them.
After that, the crop is mown using a mower-conditioner and baled once it
has dried. This method decreases fibre yield but will result in a higher
seed yield.
Method a) is most used in the Le Mans region, method b) is more popular
in the Troyes region, in both regions big round bales are most popular,
high density square bales do not work with hemp.

An average hemp crop will yield 6 to 8 t / ha of stem (16% humidity) and
600 to 1000 kg of grain (10% humidity). Bark content in the stem is 35 to
40 %. This is high relative to the bark content of about 30% which is
obtained in the Netherlands with the French varieties. The lower bark
content in the Netherlands may be due to the lower plant density and the
higher yield level in the Netherlands.


In France two factories process hemp bales. If present, the seed is
separated from the stems, the stems are then separated into bark and wood
by means of a hammer mill. The details of this separation technology were
not revealed as it is secret. One of these processing factories, "Les
Papeteries de Mauduit" (part of the Kimberly Clark group) is at Le Mans
and processes both hemp and flax. Both hemp bark and flax fibre produced
in this factory are pulped and made into paper at another factory of the
"Papeteries du Mauduit" at Quimperle (Brittany). The other hemp
processing factory "La Chanvriere de L'Aube" is a cooperative situated at
Bar sur Aube near Troyes. This factory sells hemp bark to pulp factories
in the United Kingdom, Germany and Italy. Both factories also sell the
woody core. This woody core is either used in particle boards or sold as
litter for pets.

The FNPC has investigated the potential of enzymatic retting as a new way
of utilising hemp in the textile industry. In this process hemp stems are
not separated by means of a hammer mill as this would shorten the fibres
too much. Instead stems are separated into bark and wood using adapted
flax breakers. The bark tissue is then cut into 30 cm-long pieces which
are carded prior to undergoing the enzymatic retting. The enzymatic retting
process dissolves pectins and thus separates fibre bundles into finer
strands of fibre cells. The product which is obtained can be spun like
cotton or flax. The hemp fibres thus obtained are more hygroscopic and
less supple than flax fibres. At this moment the FNPC is looking for 85
million French francs (FF) to set up a retting factory which would process
3500 tonne of hemp bark per year.


Some indications of prices were supplied. One tonne (metric tonne is about
1.1 US tons) of hemp straw (16% humidity) is worth about 500 FF. (About $
100 US). One tonne of hemp bark (at 10 to 12% humidity) was worth 2000
to 2200 FF at July '92 market prices. The market is very poor as a result
of large surpluses of flax tow. Normally one tonne of high quality hemp
bark should fetch 3000 FF. hemp bark of lesser quality (e.g. containing
too much woody core) about 2500 FF. One tonne of woody core (not cleaned
or processed) is worth 200 to 300 FF. Grain (10% humidity) was worth
about 250FF / 100 kg. Generally prices range from 200 to 400 FF / 100 kg
of seed. Seed for sowing is sold at 1600 FF / 100 kg within France and for
2000 FF / 100 kg to countries abroad.


In France hemp is a small crop. At this moment the economic feasibility is
severely handicapped by low prices of flax byproducts (tow) which are used
in the same pulps and paper products as hemp. The Federation Nationale des
Producteurs de Chanvre however thinks hemp has a future in France, and
works vigourously to promote hemp.
Mr. Mathieu thinks economic prospects will improve as flax prices are bound
to rise. He also feels that the general attitude towards hemp is positive,
as it is a crop which requires a low fertilizer input and which is grown
without pesticides. Furthermore, as pulping of trees is increasingly
criticised, annual fibre crops are looked upon positively.

The optimism of the FNPC is reflected in their breeding programme aiming at
producing commercial THC-free hemp varieties and in their efforts to
develop technology to open up the textile market for hemp fibre.

The breeders in the Dutch Hemp Programme try to make very late varieties
which will produce high stem yields. Mr. Mathieu challenged this approach
by pointing out some disadvantages linked to it. A late variety does not
yield any seed, so neither the sale of the seed nor the EEC subsidy for the
seed enter in the financial result of the crop. Conservation of a late
variety is difficult as artificial drying is expensive and ensiling may
affect fibre quality. An early variety may yield 800 kg / ha of seed which
corresponds to Dfl 1500 (seed + EEC support). Stem yield of an early
variety might be 3 tonne / ha less, which corresponds to Dfl 500 - yielding
an advantage of Dfl 1000 - / ha for the early variety. Even though these
are rough estimations, it might be very much worthwhile to add an option to
the Hemp Research Programme by enlarging the breeding programme to include
the breeding of an early dual purpose variety.

The harvest of an early hemp variety, yielding both stem and seed does not
necessarily take place earlier in the season, as the seed requires time to
fill and ripen. At harvest however the crop is in a different development
stage, having less leaves and possibly a dryer stem, also stem yield is
lower. Field drying of a fully vegetative high yielding late variety may
be difficult, whereas for an early dual purpose hemp it might be an option
worthwhile considering.

In conclusion, the visit to Mr. Mathieu and Mr. Beherec of the FNPC was
very interesting and stimulating. Interesting to learn about their work in
breeding and agronomy which is based on several decades of work with hemp.
Stimulating to meet colleagues who work with hemp in the "real world" and
who show thus that hemp is not only a crop of academic interest but may
also be of economic significance to farmers.


Bredemann G., K. Garber, W. Huhnke & R. von Sengbusch, 1961. Die Zuchtung
von monozischen und diozischen, faserertragreichen Hanfsorten. Zeltschrift
fur Pflanzenzuchtung 46, 3 235-246.

Hennink S, E P M de Meijer & H M G van der Werf, 1991. Report of a visit
to the All-union Scientific and Research Institute of Bast Crops, Glukhov,
Ukrainian SSR. CPRO-DLP, Wageningen, 14 pp.

Meijer E P M de, H M G van der Werf & W J M Meijer, 1990. Veredeling en
gewaskennis van hennep in Hongarije. Reisverslag 5 en 6 juli 1990.
CABO-DLO, Wageningen, 14 pp