|Riassunto in Inglese:|
Highly efficient mechanical harvesting systems for the hazelnut crop can reduce labor need and associated costs, thus increasing profitability. Moreover, high field capacity allows repeated runs through the orchard, and consequently a shorter on-ground stay for nuts, thus improving product quality. Unlike vacuum harvesters, in which an air stream is used to suck fruits from the ground and for the cleaning, pick-up harvesters, in which a rotating-brush is used to lift fruits while cleaning mechanisms remove debris, can work with a grass ground cover, thus reducing dust problems in the groves, with no need for herbicides. The Jolly 2800 harvester developed by GF, was tested for its operational performance, productivity and work quality. This tractor-drawn unit was connected to the three-point hitch of a tractor with a driver seat rotation system to invert the driving direction. Field tests were carried out on different picking surfaces. Good results were obtained both on bare ground (rolled for a smooth orchard floor) and on natural ground covered with grasses, mown before fruit fall. The machine can harvest exactly in the same way with a considerable weed growth after frequent rainfall during the harvest period. The tests resulted in a good hourly productivity (2.6 t h-1), and high operative working capacity (0.4 ha h-1), thus allowing repeated runs. A low dust production was observed, with less air pollution in the orchard environment, since the pick-up brush and the transfer/cleaner augers are enclosed, and no fans are installed for product cleaning. The multiple step cleaning process, with augers that move the product through tube chambers, with revolving cylinders for removing leaves and metal meshes for separating dirt from the product, allows a high degree of product cleaning (97%). A fine adjustment of the distance between the picking head and the orchard floor and a wide range of brush rotating speeds, resulted in a good picking efficiency with a low percentage of fruit losses on the ground (8%).