Europ. J. Agronomy 22 (2005) 375–389 Biomass yield and energy balance of giant reed (Arundo donax L.) cropped in central Italy as related to different management practices L.G. Angelini a,∗ , L. Ceccarini a , E. Bonari b a Dipartimento di Agronomia e Gestione dell’Agroecosistema, Via S. Michele degli Scalzi 2, 56100 Pisa, Italy b Scuola Superiore di Studi Universitari e di Perfezionamento S. Anna, Piazza Martiri della Libert` a, 33, 56100 Pisa, Italy Received 12 May 2003; received in revised form 24 March 2004; accepted 12 May 2004 Abstract In order to evaluate the possibility of reducing energy input in giant reed (Arundo donax L.) as a perennial biomass crop, a field experiment was carried out from 1996 to 2001 in central Italy. Crop yield response to fertilisation (200–80–200 kg ha -1 N–P–K), harvest time (autumn and winter) and plant density (20,000 and 40,000 plants per ha) was evaluated. The energy balance was assessed considering the energy costs of production inputs and the energy output obtained by the transformation of the final product. The crop yield increased by +50% from the establishment period to the 2nd year of growth when it achieved the highest dry matter yield. The mature crop displayed on average annual production rates of 3 kg dry matter m -2 , with maximum values obtained in fertilised plot and during winter harvest time. Fertilisation mainly enhanced dry matter yield in the initial period (+0.7 kg dry matter m -2 as years 1–6 mean value). The biomass water content was affected by harvest time, decreasing by about 10% from autumn to winter. With regard to plant density, higher dry matter yields were achieved with 20,000 plants per ha (+0.3 kg dry matter m -2 as years 1–6 mean value). The total energy input decreased from fertilised (18 GJ ha -1 ) to not fertilised crops (4 GJ ha -1 ). The higher energetic input was represented by fertilisation which involved 14 GJ ha -1 (fertilisers plus their distribution) of total energy costs. This value represents 78% of total energy inputs for fertilised crops. Giant reed biomass calorific mean value (i.e., the calorific value obtained from combustion of biomass sample in an adiabatic system) was about 17 MJ kg -1 dry matter and it was not affected by fertilisation, or by plant density or har- vest time. Fertilisation enhanced crop biomass yield from 23 to 27 dry tonnes per ha (years 1–6 mean value). This 15% increase was possible with an energy consumption of 70% of the overall energy cost. Maximum energy yield out- put was 496 GJ ha -1 , obtained with 20,000 plants per ha and fertilisation. From the establishment period to 2nd–6th year of growth the energy production efficiency (as ratio between energy output and energy input per ha) and the net energy yield (as difference between energy output and energy input per ha) increased due to the low crop dry biomass yield and . ∗ Corresponding author E-mail address: angelini@agr.unipi.it (L.G. Angelini). 1161-0301/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.eja.2004.05.004