Exploitability of cultivated and wild cardoon as long-term, low-input energy crops

The potential ability in terms of biomass, achenes, oil and energy yield of two Cynara cardunculus L. genotypes (one cultivated cardoon and one wild cardoon) was evaluated along a 7-year experiment. It was carried out in a marginal farmland of Southern Italy, with low soil fertility and minimal external inputs. Under these conditions, they reached an annual harvestable biomass ranging from 0.74 (wild cardoon) to 1.46 kg m^−2 (cultivated cardoon) and an energy yield ranging from 13.8 to 27.5 kJ m^−2. The lower heating value of biomass (including achenes) was on average 18.2 kJ kg^−1, while the oil yield from achenes varied between 25.1 and 25.7 g 100 g^−1 of dry matter. The cultivated cardoon was able to produce high yields until the fifth season and therefore is prone for medium long-time cropping systems. Conversely, wild cardoon showed a most stable yield pattern and plant survival over seasons, suggesting its particular suitability for perennial cropping systems in Mediterranean marginal areas.