Bast II

AGRONOMY

Fertilization and rotation

In most cases fertilization of hemp in the Soviet Union is carried out with
chemical fertilizers only. Depending on the soil and the expected yield,
60 to 120 kilograms [kg] of Nitrogen [N] and Phosphorus [P] and 80 to 140
kg of Potassium [K] are applied. Fertilization affects fibre quality by
its effect on plant density. The more N fertilizer is applied, the smaller
the number of plants at harvest and the larger mean plant size will be.
Large plants have a lower bast fibre content than small plants.
In the Glukhov regon hemp may be grown after each of the crops in the
rotation (cereals, potatoes, maize, clover). Hemp is considered to be
self-compatible, it sometimes is grown for 5 to 10 years continuously on
the same field, with no aparent effect on yield. In a field experiment at
Glukhov hemp has been grown continuously for 60 years. The experiment
contains fertilization levels ranging from no fertilization (yield 880 kg
of stem / ha) to 40 tonnes of manure / ha (yield 7000 to 8000 kg of stem
/ ha). Reported weights of straw and fibre include respectively 20% and
13% moisture.

Sowing

Hemp is usually sown in the second half of April. In most cases hemp seed
is treated with TMTD. On good soils 450 seeds per square meter are sown
for fibre hemp, on poor soil 500 to 550 seeds are used. Row width is 7 to
12 cm. In a good crop of fibre hemp 300 plants per square meter will be
present at harvest. When hemp is grown for seed production, plant density
at harvest varies from 30 to 180 plants per square meter, depending on the
variety.

Weed control
In fibre hemp weed control is not necessary. In seed hemp, which is sown
at a lower plant density, herbicides are used. Against monocotyls: Nabu,
Targa (quizalo-fop-ethyl), Zellek (manufactured by Dow), Fusilade
(fluazifop, 1.5 to 2.5 liters / ha) and Iloxan (diclofop, 2 to 3 l / ha).
Against dicotyls: Ballan (benefin), Dual (etolachlor), Lenacil (venzar),
Pyramin (pyrazon). A mixture of Dual (1.5 l / ha) and Lenacil (1.2 l /
ha) is often used.

Pests and diseases

Two insect species (Lepidoptera) may cause damage to hemp: Grapholita
delineata and Ostrinia nubilalis. Against both insects, Bacillus
thuringiensis and Trigogamma spp. are used. Against Psylliodes attenuata,
the hop flea beetle, a seed treatment is available, the composition of
which is secret.

Harvesting and processing

About 70% of the hemp area of the Soviet Union is harvested for fibre only.
Harvest takes place at "technical maturity," that is, when the male
plants are shedding pollen. At Glukhov this stage generally is reached by
the end of July or early in August. Seed ripeness occurs one month later.
By the end of July a hemp crop will yield 7 to 8 tonnes of stem (20%
humidity) ha and 1.7 to 2 tonnes of bast fibre (13% humidity) ha.

Prior to harvest, the crop will be defoliated, either by mechanical means
or by spraying Magnesium chlorate. Most of the hemp is dew retted,
depending on the weather, dew retting may take 10 days to one month. Other
common techniques are warm water retting and chemical retting. In some
factories hot steam is used to separate the bast fibre from the rest of the
stem. The best fibre quality is obtained from warm water retting. High
quality hemp stems are tyically 1.50 to 2.00 m long, their diameter (at
half height) will be 5 to 7 mm.

HARVEST TECHNOLOGY

The department of mechanization and harvest technology develops prototypes
of new machines for hemp. The machines shown to us are listed here:

* Harvester. This machine mows the hemp and ties it into bundles without
damaging (breaking or crushing) the stems. Careful handling of the stems
is important when the fibre is used for textile. For hemp which is used
for pulp this is less important. The machine leaves the bundles in the
field to dry. This machine can handle hemp of a length of up to 3.5 m.
* Mechanical defoliator. Research into mechanical defoliation has started
in order to find an alternative to chemical defoliation.
* A machine which turns hemp stems in the course of dew retting.
* A machine which picks up hemp stems after dew retting and makes bundles.

* A big baler which picks up hemp from the field while driving diagonally
across the stems.
* A machine which is used to unroll big bales in the processing factory.

We were told that the lack of harvesting machines is the main factor
limiting the area of hemp grown in the Soviet Union. In the republic of
Uzbekistan 20,000 ha. of kenaf is grown. Mechanization is similar to that
used for hemp.

PULP AND PAPER TECHNOLOGY

Among other topics, the Ukrainian Pulp and Paper Research Institute at Kiev
investigates pulping, paper making, composite materials and paper
recycling. A paper in English, listing in full the activities of the
institute can be obtained from the authors of this report. The institute
also investigates the use of annual crops (flax, hemp, reed, rice straw)
as a raw material for paper making.

Currently two pulp plants are operating in the Ukraine, both use aspen wood
as raw material, they produce paper and board. The feasibility of a third
pulp plant is being studied. One of the product lines of this new plant
might be based on hemp bast fibre. Hemp bast pulp might be used for three
paper grades:

* Cigarette paper. At present cigarette paper is imported. The required
technology is available in the Ukraine, the pulp would consist of 50% hemp
bast fibre and 50% wood.

* Document paper (high strength, bank notes). This paper usually is
produced using the polluting Kraft method. The quality of document paper
does not depend so much on fibre lengths but on the pulping and bleaching
techniques used. Dr. Krotov proposes a new non-polluting method for making
document paper from bast fibre. When used on the woody core this material
will yield a relatively good pulp. The method is described in a paper
which can be obtained from the authors of this report. This new method is
not yet used, as the machines which are required cannot be built in the
Ukraine.

* Reinforced paper for the sausage industry. This type of paper is
currently bought from the Dexter company. The technology required for
making sausage paper is being developed at the Leningrad (St. Petersburg)
pulp and paper institute. For this paper grade the fibres should be as
long and strong as possible.

Dr. Krotov thinks that the conservation of wet hemp stems ("ensiling," as
is considered in the Dutch hemp programme) prior to processing in the pulp
factory is a viable option, as appropriate conservation products are
available. These chemicals will conserve the hemp stems and initiate the
pulping process. The institute would be interested to cooperate with Dutch
researchers on this topic. In order to be best suited for paper
production, hemp stems should contain as much bast and as little wood as
possible. The woody core of the hemp stem is relatively hard to delignify
(relative to aspen). A lower lignin content in the wood would therefore be
desirable. Experiments carried out in cooperation with the research
institute at Glukhov have shown that the crop development stage at harvest
has little effect on the delignification process of the woody core.

CLOSING REMARKS

Literature, seed material and results will possibly be exchanged. For
example CPRO-DLO has evaluated a collection of hemp accessions, including
some Russian varieties. It would be interesting to compare results
obtained in the Soviet Union with those obtained under Dutch conditions.
This report will be handed to colleagues involved in the Dutch National
Hemp Programme which will probably lead to contacts on other fields of
research besides breeding and agronomy. It would be a pleasure for us if a
countervisit to Holland could be arranged in the future.


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