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Currently the biodiesel chain is promoted by the European energy policy. For the Italian scenario the sunflower is one of the most important crop to be considered for biodiesel production but the chain is not fully profitable. This problem could be solved with the increase of farm incomes through a proper valorization of by-products. From this point of view the oilseed crop is not considered only for oil production but also for producing multiple products with the same economic value. This is the main inspiring concept of the Extravalore project. The sub-project “Raw Materials” investigated about the possible influence of different agro-technics performed in three distinct geographical environments (Northern, Central and Southern Italy) on the characteristics of by-products obtained from sunflower crop. A national net of experimental tests was set during the 2010–2013 period in order to evaluate the adaptability and the potential production of high oleic sunflower hybrids. 7 seed companies supplied the 20 genotypes assessed in total (18 high oleic hybrids and 2 as control), 11 of them were evaluated all the three years. Achene yields of tested high oleic hybrids were extremely variable: from 2.05 t ha −1 to 4.04 t ha −1 in Northern Italy, from 2.50 t ha −1 to 4.24 t ha −1 in Central Italy and from 2.09 t ha −1 to 2.68 t ha −1 in Southern Italy. For this reason, it was necessary a precise characterization of varieties before their cultivation. The cultivar screening showed general difficulty for high oleic hybrids to reach the performances of achene and oil yields of the conventional ones. In particular, LG55.57HO and PR64H31 resulted the best high oleic cultivars for Northern Italy; many of the high oleic tested cultivars performed well for Central Italy and also for Southern Italy but with a higher variability. The highest potential production was registered in Central Italy; Northern Italy gave decreased but similar results, despite the different latitude; in Southern Italy the productions were 20–30% lower, even with the irrigation support. All high oleic tested cultivars showed oleic acid content in lipid fraction always above the 84% in Central Italy, meaning a stability of the character, very important for the biodiesel production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pilot level aerobic co-composting of digestate and biogas feedstocks was conducted. • Composting reduced C/N ratio, release of trace elements, and phytotoxicity. • Enzyme activities were influenced by OM content and release of trace elements. • Enzyme activities could be compost maturity indicators. The current study evaluated the quality of agricultural waste digestate by composting or co-composting with biogas feedstock (maize silage, food processing waste, or poultry litter). Temperature, phytotoxicity, C/N ratio, water extractable trace elements, and 14 enzyme activities were monitored. Temperature dropped earlier in digestate and maize silage co-composting pile, reducing time to maturity by 20 days. Composting and co-composting reduced phytotoxicity and C/N ratio, but increased immobilization of Al, Ba, Fe, Zn, and Mn at least by 40% in all piles. All the enzyme activities, except arylsulfatase and α-glucosidase, increased at the maturity phase and negatively correlated with organic matter content and most of trace elements. Post-digestate composting or co-composting with biogas feedstock is a promising strategy to improve digestate quality for fertilizer use, and selected enzyme activities can be indicators of compost maturity and immobilization of trace elements. [ABSTRACT FROM AUTHOR]