The conventional production of natural fibres from e.g. hemp or flax is based on field drying and retting of fibre straw. Since at the usual harvest time in September, weather conditions are often problematical for harvesting and retting hemp, a weather-independent post-harvest technique was studied. The harvesting of hemp by means of a chopper followed by anaerobic storage is favourable for the farmer because the weather risk can be avoided. Additional steps are the same as those for ensiling of fod- der. As a further advantage of this novel processing tech- nology, the whole plant material will be processed to form final products such as insulation materials and fibre boards, or semi-finished products for injection moulding. At present, a pilot plant with a processing capacity of 1 t per hour hemp silage is being built up and tested. The in- vestigations regarding storage costs and appropriate stor- age technology have shown that both stack silos and film silos are capable of preserving the raw material for more than one year. Initial results of the preservation of hemp in film tubes are presented.
