Field evaluation of Arundo donax clones for bioenergy production

• Twenty four clones of giant reed collected worldwide were studied in a randomized field trial.
• Yield performance of different clones was linked to stem size and tillering ability.
• Biomass quality and methane potential were influenced by clone.
• Biomass with low lignin had higher biochemical methane potential.

A collection of 24 clones of Arundo donax, from different geographical areas in Italy, Europe, and China, were evaluated during the first 3 years from transplant. A field trial with 3 replicates was set up in the Po valley (northern Italy) in a sandy loam soil. At harvest, at the end of the second and third year after plantation, biomass yield, average stem number, average stem diameter, and single plant area were determined for each clone. For a selection of clones, chemical analysis and biochemical methane potential (BMP) were also performed. A large variation among clones was found for all the biometric parameters considered and also for biomass yield. It was interesting to note that some clones, while achieving similar biomass yield, had contrasting growth patterns, with some clones producing just a few large stems and others producing many thin ones. As a consequence, a different number of stems per plant area was also found among clones. Chemical analysis highlighted a significant difference among clones for ash (from 5.3% to 8.1%), lignin (from 6.9% to 10.6%), and hemicellulose (from 25.1% to 29.2%) content, while cellulose content was on average 43.4%. BMP ranging from 147 ml g−1 VS to 243 ml g−1 VS and was partially affected by lignin and ash content.