## 1 Introduction  
The fast growth rate, high biomass yield, limited input demand, ability to grow in different soil types and under different climatic conditions, high resistance to pathogens and long drought periods, strong weed competition, and high calorific value [1] are some of the most important characteristics of the giant reed (_Arundo donax_ L.), making it one of the main bioenergy crops [2]. Lignocellulose from the giant reed represents a significant source for paper [3], rayon [4], second-generation ethanol and biopolymers [5], biogas production [6], and for the raw materials of biodiesel production [7, 8]. Moreover, its good yield coupled with the low level of input needed for its production could provide a positive energy balance. _Arundo donax_ is adapted to all soil types and different weather conditions, but it is very important to determine the most appropriate harvesting technique in order to obtain the highest level of biomass possible, together with a low level of moisture during harvesting and a small fine fraction [9]. Several studies have confirmed that the key cost components in the logistic chain of herbaceous crops are transportation, adopted logistics, and field operations, such as biomassharvesting [10; 11; 12; 13; 14; 15]. Until a few years ago, the propagation system was critical; then, mechanized techniques using rhizomes [16] were developed, which reduced the establishment costs [17]. The main bottleneck of this herbaceous crop is the low bulk density, which causes high logistic costs [18], and only the baling technique can reduce the harvest costs [19; 20]. Modern baling machines, both round and square balers, can increase the final density, but they require a lower moisture level in the crop [21] to enable longer storage and reduce the fermentation risk. The moisture at harvest time is the main parameter that determines the success of the storage phase, and this problem can be reduced through the infield densification of dried biomass harvested in round or square balers [22; 23]. The same test was conducted with a self-propelled forage harvester (SPFH) that chips dry biomass, but the low bulk density of the chipped material and the lack of an efficient compaction field system limits the applicability of this system by raising the harvest costs [18; 22]. These parameters allow the immediate use of it as a fuel for thermo valorization, and the low moisture of the biomass prevents the risk of unwanted fermentation during storage, thanks to the improvement of air permeability. A greater moisture content limits the possibility of biomass valorization in solutions of fresh biomass (second-generation ethanol and biogas) [24]. The machine adopted for moving and shredding the crops is a new commercial machine with a specific rotor for herbaceous crops that communutes the plants into small pieces, while the harvesting of dry materials is carried out with a trailed round baler, conventionally adopted for haymaking crops. Several studies have provided interesting information about _Arundo donax_ compared with other herbaceous crops in terms of its biomass and responses to different harvest technologies, fertilizers, and other cultivation techniques [25; 26; 27].  
In the southern areas of Italy, the giant reed is a newly introduced energy crop for combustion in thermo valorization plants, and its use has sparked great interest [28]. The bales are classified as high quality if they have a low moisture content and a high bulk density [29].  
The aim of this study was to analyze two-steps (shredding and baling) of the harvesting system of _Arundo donax_ in southern Italy. We considered two production levels and two different settings of the mechanized harvesting line.