Test of a new mobile machine for comminuting and cleaning rootstock waste

A new shredder was designed for comminuting small-size rootstocks from the termination of orchards and short-rotation plantations. The new shredder is lighter than any similar models available on the market and is fitted with an integral star screen: these innovative characteristics allow the machine to work in-field, leaving dirt on site and packing denser loads. The preliminary test conducted in this study lasted 13.2 h and produced 15 full containers, or 123 t of fresh chunks. Researchers measured the time required to fill each container, and associated it with its net weight. Samples were collected from each load in order to determine product moisture and dirt content. Productivity ranged most commonly between 8 and 10 t of fresh chunks (or 38 and 50 m3 of loose chunks) per scheduled hour, inclusive of all delays. Net shredding productivity was much higher and peaked at 17 t of fresh chunks or 80 m3 of loose chunks per hour, excluding delays. The shredding cost varied between 24 and 30 EUR t-1 of fresh chunks, including transportation to the plant yard. Prolonged storage at the field edge and effective screening resulted in a dramatic reduction of water and soil content, which were measured at 23% and 1% respectively.