Advantages and disadvantages of harvesting green and dry kenaf stems

Factors   Harvesting of green stems   Harvesting of dry stems
Loss of production   Generally minimum as the crop remains in the field for a very modest period of time after having reached maximum development in terms of yield.   They can be tall due to the flattening of the plants or due to attacks of fungus that occur in the field in poor weather conditions during the drying period. A partially dry crop can reactivate the growth of the plants from the lowest nodes in the event of rain.
Land occupation   Minimum. The crop can be harvested at the stage when it produces maximum yield per unit of time.   The land is occupied for a maximum of one or two months after the end of the development stage, namely until such time as the plants are completely dry.
Post-harvest processes   No problems arise if the stems are used immediately by a paper mill. If, on the other hand, they have to be stored, they must be dried after harvesting.   The process and the storage at the paper mill are facilitated by the low humidity content of the material that is delivered to the paper mill at the atmospheric dry stage.
Juice from the stems   Part of the juice contained in the stems can be extracted in the field. This restoration of nutritional elements to the soil can also reduce the quantity of chemicals required for the pulping process. The extraction of the juice from the stems also facilitates the separation of the bast fibres from the  woody ones.   The juice of the stems cannot be recovered.
Efficiency of the operational capacity of harvesting   Higher harvesting operational capacity is needed at peak times. This problem is lesser in regions where production is possible all year round if the crops of different farmers can be staggered over time.   As the time of harvesting can be planned, based on requirements, there are more opportunities to optimise the efficiency of harvesting operations.
Weight of harvested material   Heavy. Green stems can be more than six times heavier than dry stems. For this reason more heavy duty machinery is required.   Minimum, because the material is almost ready for being sold on the market.
Speed of harvesting   Reasonably high.   Sometimes low due to the frequent entanglements and consequent blocking of the machinery. This problem can be overcome if harvesting machinery is designed specifically for the harvesting of kenaf stems.
Environmental problems   None. But, if it is not used a machine equipped with a cutting device to cut the apical parts and pick up the leaves separately, then the plants should be defoliated with drying products before harvesting.   Serious potential problems due to: the transport of the herbicide mixing on the nearby  crops, the drying residual on the ground and in the irrigation water, the harmful effects to the operators, farmers and the population in general.
Leafy material   Can be used as animal fodder.   Cannot be recovered, but the dry leaves, scattered over the terrain restore nutritional elements to the soil.
Other kenaf products   Integrated process to produce seeds, leaf panels and potentially also the extraction of the juice from the stems.   Only the stems can be used for the production of cellulose fibres.
Source: Kirshbaum M.U.F. - "Prospects for a Pulp and Paper Industry in Australia" Department of Primary Industries and Energy - Bureau of Rural Resources - Bulletin No. 9 1991.

Source: "Il kenaf, non solo una nuova materia prima cellulosica" - G. Mignoni