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The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. Soil organic carbon (SOC) of an older poplar plantation was used to estimate via a regression the SOC loss due to SRC establishment. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled and GHG emission offset due to fossil fuel substitution was credited to the SRC site considering the C intensity of natural gas. Emissions due to the use of the biomass (FEXP) were also considered. The suitability was finally assessed comparing the GHG budgets of the two sites. FCO2 was the higher flux in the SRC site (-3512 ± 224 g CO2 eq m-2 in two years), while in the REF site it was −1838 ± 107 g CO2 m-2 in two years. FEXP was equal to 1858 ± 240 g CO2 m-2 in 24 months in the REF site, thus basically compensating FCO2, while it was 1118 ± 521 g CO2 eq m-2 in 24 months in the SRC site. This latter could offset -379.7 ± 175.1 g CO2 eq m-2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN weighed 2 and 4% in the GHG budgets of SRC and REF sites respectively, while the SOC loss weighed 455 ± 524 g CO2 m-2 in two years. Overall, the REF site was close to neutrality in a GHG perspective (156 ± 264 g CO2 eq m-2), while the SRC site was a net sink of -2202 ± 792 g CO2 eq m-2. In conclusion the experiment led to a positive evaluation of the conversion of cropland to bioenergy SRC from a GHG viewpoint. [ABSTRACT FROM AUTHOR]

The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (...), whereas chambers were used to measure N2O and CH4 emissions from soil. Soil organic carbon (SOC) of an older poplar plantation was used to estimate via a regression the SOC loss due to SRC establishment. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled and GHG emission offset due to fossil fuel substitution was credited to the SRC site considering the C intensity of natural gas. Emissions due to the use of the biomass (FEXP) were also considered. The suitability was finally assessed comparing the GHG budgets of the two sites. ... was the higher flux in the SRC site (-3512±224 gCO2 eq m-2 in two years), while in the REF site it was -1838 ± 107 g CO2 m-2 in two years. FEXP was equal to 1858±240 gCO2 m-2 in 24 months in the REF site, thus basically compensating ..., while it was 1118±521 gCO2 eq m-2 in 24 months in the SRC site. This latter could offset -379.7±175.1 gCO2 eq m-2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN weighed 2 and 4% in the GHG budgets of SRC and REF sites respectively, while the SOC loss weighed 455±524 gCO2 m-2 in two years. Overall, the REF site was close to neutrality in a GHG perspective (156±264 gCO2 eq m-2), while the SRC site was a net sink of -2202±792 gCO2 eq m-2. In conclusion the experiment led to a positive evaluation of the conversion of cropland to bioenergy SRC from a GHG viewpoint. [ABSTRACT FROM AUTHOR]