## 2 Material and Methods
### Machine Characteristics and Performance  
The study on the harvesting of the giant reed took place in March when the biomass of the crop was shredded and spread on the surface of the field. In the first phase, the operations involved cutting, shredding, and spreading without windowing with the rear mounted shredder. The machine used was a biotriturator produced by the company Nobili S.r.l. (Bologna, Italy), which combines all of the above-mentioned operations. The Windrower Shredder (WS) series was specifically designed and developed for this category of energy crops [30]. It was composed of a main rotor with 40 hammers installed on 8 lines and driven by 5 parallel belts (Figure 1) and it was rear-mounted (Figure 2) using three-point linkage on a four-wheel drive tractor with a 206 kW engine (make: Fendt, model: 828 Vario). Figure 1: Hammer rotor. Figure 2: The shredding machine adopted for the tests (Nobili WS 320 BIO). Before harvesting, some tests were carried out to monitor the performance of the machine in terms of its settings (working speed and rotor speed). In the first two years of development, the test field was divided into two and each part was treated differently. One part was irrigated and fertilized as described; the other only underwent transplant irrigation. In the following years, the plants were treated in the same way without external intervention. However, two levels of production--high and low yield--were characterized. The data were obtained from manual harvesting of a specific sample area of 4 m\({}^{2}\). For the two yield classifications (high and low), we used two working speeds obtained with the same gear but varying the motor speed from 2200 to 1890 revolutions/minute (r.p.m.) and using two rotor rotational speeds (1170 and 1000 rpm). For each of the eight settings identified by two passages for the entire length of the test field, three replicates were monitored (Figure 3). The manufacturer of the biotrutrator indicated that it was specifically designed and developed for use at a main rotor speed of 1000 rpm; this was applied by setting the power take off of the tractor to this speed. The results of the preliminary tests were used to assess the level of crushing and the obtainable cutting height at different advanced and rotor speeds. They were considered to be the limit values of crop crushing that could give a maximum length of 100 cm of unshredded material (1000 r.p.m. main rotor) and a minimum working speed (1800 r.p.m. engine speed) that allowed good precision cutting. The machine used to harvest the dry-biomass was a roundbater (Claas model Rollant 250) trailed by four wheels and driven by agricultural tractor (Valtra model N141). The machine adopted for baling has specific features for the management of different categories of crops, for example, the compression chamber is fixed and composed of multiple parallel roller systems and a specific feeding device. This compression system is adapted for dried and wet biomass, is equipped for tying on both mesh or twine, and is quickly editable by the operator cab. For the test, it was decided to use mesh tying, as this is able to reduce the loss of small particles, especially during the tying phase. It is important to choose the most suitable tying system (on mesh or twine) to suit the characteristics of the biomass crop and influence the baling costs. To determine the round bater efficiency, we recorded the turning times at the field end, and the periodical time losses due to the tying and discharge of bales were also considered. We assumed that the appropriate performance measure of the investigated machine was the working time according to American Society of Agricultural and Biological Engineers (ASABE) [32; 33].