In topping, most of the leaves and flowers from the top of the plant are removed prior to harvesting. The cutting has to be done in such a way that as little sand as possible is picked up, while maintaining optimum yield. It is best carried out with a so called row distance independant cutter bar in front of a forage harvester. After chopping the hemp can be ensiled at the farm. To optimize the processing of hemp into pulp over the year drying and ensilage was studied as a conservation storage technique.
Ensilage is appreciable cheaper than drying and more reliable.
The paper quality of ensiled hemp is slightly less than of the dried hemp, but still of acceptable quality. As the differences between these two fractions merit a separation into two separate raw materials, research was carried out into this aspect. Separation can be carried out before of after storage at farm level or at the pulping facility. As harvest takes place in Sept., a rather wet period, dry separation was discarded. Two options were selected, sieving and flotation.