Prototype for the harvesting of cultivated herbaceous energy crops, an economic and technical evaluation

The scope of this study was to evaluate a multi-purpose prototype, the biotriturator, for the harvesting of biomass species cultivated in Northern Italy that would allow the baling of biomass to reduce the handling and storage costs. Harvesting trials were conducted on two herbaceous perennials: giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.), plus a herbaceous annual fiber sorghum (Sorghum bicolor L. Moench). A technical and economic evaluation compared three harvesting systems in which the biomass was shredded with the biotriturator. The first system was a cutting-shredding-baling in the same operation. The second required two successive steps, the first was cutting and shredding with the biotriturator, the second was baling. The third harvesting system required three successive steps: cutting and shredding with the biotriturator, windrowing with star wheel rakes and baling. While the first and second systems were evaluated on the two perennial crops the third was evaluated on an annual crop. Considering the hectares that can be covered by the biotriturator (170 ha of sorghum and 270 of switchgrass, with an average annual use of 200 h) and the total harvest cost (9.9-12.1 € Mg-1 dry biomass), the harvesting system represents an effective solution for situations like that in Italy, where average farm sizes are small.