Long-term evaluation of biomass production and quality of two cardoon (Cynara cardunculus L.) cultivars for energy use

Cardoon (Cynara cardunculus L.) is an herbaceous species indicated as one of the most suitable energy crop for southern European countries. The aim of this work was to outline the productivity of two cardoon cultivars, Bianco Avorio (BA) and Gigante di Romagna (GR), over 11 years of cultivation in rain fed field conditions in the temperate climate of Central Italy. The quantitative and qualitative aspects of its biomass (calorific value, ultimate and proximate analyses, ash composition) as well as its energy balance (energy efficiency, net energy yield) have been determined. Crop dry yield was not different between the two cultivars and it was rather stable with a mean value (averaged from year 3 to 11) of 14 and 13 t ha−1 for GR and BA respectively. Furthermore the biomass dry matter content was higher in BA than GR (51% vs 42%). The chemical analysis of cardoon biomass showed a similar composition in both cultivars with good calorific value (15 MJ kg−1) but with an ash content (13.9% d.w.) higher than other herbaceous energy crops. The total energy input was higher in the establishing than in the following years, however from the planting year onward, both cardoon crops were characterised by a positive energy balance. Even if its mean net energy is lower than other perennial energy crops (182 GJ ha−1 year−1), cardoon can be easily propagated by seed with important advantages for crop management and production costs. The results confirmed cardoon's good biomass yield and favourable energy balance even in cultivation systems characterised by limited water input. Moreover future works are necessary in order to improve cardoon biomass quality and to evaluate the possibility of using it in blends with other biomass sources.

[1]  G. H. Heichel.  Assessing the fossil energy costs of propagating agricultural crops. , 1980 .

[2]  George H. Hargreaves,et al.  Reference Crop Evapotranspiration from Temperature , 1985 .

[3]  W. Lockeretz,et al.  Energy inputs for nitrogen, phosphorus, and potash fertilizers. , 1980 .

[4]  M. D. Curt,et al.  The potential of Cynara cardunculus L. for seed oil production in a perennial cultivation system , 2002 .

[5]  Enrico Bonari,et al.  Biomass yield and energy balance of giant reed (Arundo donax L.) cropped in central Italy as related to different management practices , 2005 .

[6]  S. A. Raccuia,et al.  Biomass and grain oil yields in Cynara cardunculus L. genotypes grown in a Mediterranean environment. , 2007 .

[7]  Giovanni Mauromicale,et al.  Possible alternative utilization of Cynara spp. , 1999 .

[8]  Enrico Bonari,et al.  Long term evaluation of biomass production of Giant reed (Arundo donax L.)to different fertilisation input, plant density and harvest time in a Mediterranean environment. , 2005 .

[9]  A. Kicherer,et al.  Combustion quality of biomass: practical relevance and experiments to modify the biomass quality of Miscanthus x giganteus , 1997 .

[10]  L. Angelini,et al.  Thermal analysis of biomass and corresponding pyrolysis products , 1996 .

[11]  J. F. González,et al.  Combustion optimisation of biomass residue pellets for domestic heating with a mural boiler , 2004 .

[12]  I. Piscioneri,et al.  Promising industrial energy crop, Cynara cardunculus: a potential source for biomass production and alternative energy , 2000 .

[13]  M. D. Curt,et al.  Industrial applications of Cynara cardunculus L. for energy and other uses , 2006 .

[14]  Enrico Bonari,et al.  Comparison of Arundo donax L. and Miscanthus x giganteus in a long-term field experiment in Central Italy: Analysis of productive characteristics and energy balance , 2009 .