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Advice on Publications Available.Tasmania has established a reputation in recent years for its initiative in developing new agricultural industries including buckwheat, pyrethrum, peppermint, fennel, boronia, wine and deer. One recent initiative has been the decision to assess the potential of hemp for paper pulp production.
In December 1991, the Tasmanian Government issued licences to the Tasmanian Hemp Company and the University of Tasmania for the import of seed and field trials of fibre-type hemp in Tasmania. The issue of these licences followed prolonged and concerted lobbying by the two directors of the Tasmanian Hemp Company, Patsy and Fritz Harmsen, who for many years had been publicising the agricultural, industrial and environmental benefits of a hemp-based paper industry in Tasmania.
Due to delays in issuing the licences, the first crop was sown too late and yields were low. A second licence was issued for 1992-93 and the trial crop grown in that season gave promising dry stem yields of about 8 tonnes per hectare. Two of the State's major paper companies conducted pulping trials using material harvested from the 1992-93 trials.
The Australian Pulp and Paper Manufacturers Ltd (APPM-now Amcor Limited), which produces a range of fine printing and writing papers, and magazine and coated papers from local hardwoods, concluded that the hemp bast (ie bark) fibres could be used to produce specialty grade papers but their cost would preclude their use as alternatives to the currently used wood pulp.
However, the other paper producer, Australian Newsprint Mills (ANM), which produces newsprint by the mechanical pulping processes of TMP and CTMP, concluded that hemp pulp could have a possible role as a reinforcing pulp to improve the strength characteristics of their pulp. ANM currently produces a blended pulp made from locally produced hardwoods and radiata pine, and a small amount of imported long fibre kraft pulp. The latter is added to provide additional strength to the pulp and it is this component which could possibly be replaced by a hemp bast pulp.
The current series of trials is being conducted as a jointly funded, co-operative study between the Department of Agricultural Science, University of Tasmania and Australian Newsprint Mills. The study commenced in early 1994 and has been conducted in close consultation with State Government authorities including the Departments of Primary Industry, Justice and Health.
The primary aim of the study is to establish whether fibre of value for paper production can be produced economically in Tasmania from non-wood fibre crops, such as hemp and flax. An integrated approach has been adopted with the study examining both the farm production system and the industrial utilisation of the fibre. Economic and ecological considerations are also included in the study.
Because of the wide scope of the study it is being conducted in close collaboration with a number of organisations with specialist expertise and facilities. ANM will conduct paper making trials and plant material will also be made available to other interested manufacturers within the State. The Department of Primary Industry will assist with economic studies and a desktop feasibility study. Other aims of the study are to define the stages of development of hemp and to develop a growth model for the crop.
The field trials are being conducted at two sites, one in southern Tasmania and the second in north-west Tasmania. A number of cultivars are being sown over a range of sowing dates. Early flowering is recognised as one of the major factors limiting yield and a late-maturing cultivar is seen as essential for a viable industry. All hemp cultivars in the trials are fibre types designated as containing less than 0.35% of the narcotic alkaloids tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidol (CBD).
The trials also include a number of flax cultivars to provide data on relative yields and paper making quality of the two fibre crops. Both hemp and flax are being investigated as dual purpose seed and fibre crops. Flax seed is the source of linseed oil and hemp seed can be used as a food ingredient in the same way as sesame seed.
The major obstacle to the sale of hemp seed as a food is that the species is currently listed on the National Food Code as a prohibited botanical for use as a foodstuff. Efforts are currently being made to have the legislation altered to exempt hemp seed in the same way as was done for poppy seed. Poppy seed is now a very valuable by-product of the Tasmanian poppy industry.
While the growing of hemp as a dual purpose fibre and seed crop could improve profitability of the crop it does pose a number of problems. The first is that delaying harvest to seed maturity will inevitably lead to a reduction in fibre quality for paper pulp production. It will also reduce the quality of the fibre for textile use if later studies show this to be a profitable option.
Secondly, delaying harvesting beyond the onset of flowering, which is the optimum harvest time when the crop is to be used for paper or textile production, greatly increases the risk of crop theft. Problems were experienced with the 1995 trials and security guards had to be employed to guard the maturing crops. It may prove necessary to have separate seed and fibre crops managed in such a way as to maximise yield and quality of the desired product while minimising security problems.
The current study is planned to continue for a further two years and future work will depend on the findings of the study and of the South Australian work which commenced this year. Licences have also been sought for trials in Victoria and NSW but have not as yet been approved. In Tasmania strong industry and university involvement coupled with the pre-existence of an established Government regulatory body has greatly facilitated the issue of the licences under which the current trials have been undertaken.
Any claims made by authors in the Australian New Crops Newsletter are presented by the Editors in good faith. Readers would be wise to critically examine the circumstances associated with any claims to determine the applicability of such claims to their specific set of circumstances. This material can be reproduced, with the provision that the source and the author (or editors, if applicable) are acknowledged and the use is for information or educational purposes. Contact with the original author is probably wise since the material may require updating or amendment if used in other publications. Material sourced from the Australian New Crops Newsletter cannot be used out of context or for commercial purposes not related to its original purpose in the newsletter
Contact: Dr Rob Fletcher, School of Land and Food, The University of Queensland Gatton College, 4345; Telephone: 07 5460 1311 or 07 5460 1301; Facsimile: 07 5460 1112; International facsimile: 61 7 5460 1112; Email:
r.fletcher@mailbox.uq.edu.au[
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GK; latest update 6 June 1999 by: RF