|Abstract in English:|
The baling of dried fibre sorghum introduces some specific problems due mostly to stalk development, height and rigidity and to the volume of green biomass to process. To improve storage and to reduce transport cost, the main aspect to consider is the achievement of a satisfactory natural drying of the plant on the ground. Previous
tests with mowers and mower-conditioners pointed out operational problems: the mowers, in relation to height and
rigidity of the stalks, showed low working capacity, while the mower-conditioners, both with rolls or spokes, were
not able to obtain a conditioning level good enough to achieve sufficient natural drying. The structure of the plant, particularly of its stalk, is such that without a continuous cleavage along the whole length, water content decreases slowlier than it would be suitable for harvesting period in Italy. Following these considerations, CRA-ING developed
a back mounted harvester prototype, connected to the rear three-point linkage of a reversible drive tractor. Such equipment permits the cutting and conditioning of the whole plant, leaving it spread on the ground, without forming windrows, so to make full use of the solar radiation for drying. When the water contents drops to the optimum value
for storing, the product can be collected in windrow and then baled with existing round balers or big balers. The adopted conditioning system is formed by six couples of longitudinal rolls, similar to those used in corn harvesting, because also the fibre sorghum is a row cultivation; each roll is provided with alternate blades and pads to press and
cleave all along the stalk while pulling down the plant. Rolls dimensions and rotational speed are such to hit the stalk every 5 cm. Under the rolls, next to the ground, a saw cuts the plants. During the first year tests in Central Italy, the idea was confirmed successful: it was possible, working at 5 km/h speed, corresponding to 1,5 ha/h effective working
capacity, to windrow and to bale the cut product after a drying time of only four days. The water content, in this period, decreased from 70% to about 25%.
Furthermore, the tests showed that the prototype allows relevant money and time savings in the fibre sorghum chain.