Annachiara Forte

Comparative attributional life cycle assessment of annual and perennial lignocellulosic feedstocks production under Mediterranean climate for biorefinery framework

Annual fiber sorghum (FS) and perennial giant reed (GR) cultivated in the Mediterranean area are interesting due to their high productivity under drought conditions and their potential use as lignocellulosic feedstock for biorefinery purposes. This study compares environmental constraints related to FS and GR produced on experimental farms (in the Campania region) using an attributional life cycle assessment (LCA) approach through appropriate modeling of the perennial cultivation. For both crops, primary data were available for agricultural management. Direct field emissions (DFEs) were computed, including the potential soil carbon storage (SCS). Giant reed showed the lowest burdens for all impact categories analyzed (most were in the range of 40%-80% of FS values). More apparent were the differences for climate change and freshwater eutrophication (respectively 80% and 81% lower for GR compared to FS). These results are due to the short-term SCS, experimentally detected in the perennial GR crop (about 0.25 ton C ha(-1) yr(-1), with a global warming offsetting potential of about 0.03 ton CO2/ton(GR dry biomass)). The results are also due to the annual application of triple superphosphate at the sowing fertilization phase for FS, which occurs differently than it does for GR. Phosphorous fertilization was performed only when crops were being established and therefore properly spread along the overall crop lifetime. For both crops, after normalization, terrestrial acidification and particulate matter formation were relevant impact categories, as a consequence of the NH3 DFE by volatilization after urea were spread superficially. Therefore, the results suggest higher environmental benefits of the perennial crop than the annual crop.

Growth and gas exchange response to water shortage of a maize crop on different soil types

The effect of water shortage on growth and gas exchange of maize grown on sandy soil (SS) and clay soil was studied. The lower soil water content in the SS during vegetative growth stages did not affect plant height, above-ground biomass, and leaf area index (LAI). LAI reduction was observed on the SS during the reproductive stage due to early leaf senescence. Canopy and leaf gas exchanges, measured by eddy correlation technique and by a portable photosynthetic system, respectively, were affected by water stress and a greater reduction in net photosynthetic rate (AN) and stomatal conductance (gs) was observed on SS. Chlorophyll and carotenoids content was not affected by water shortage in either condition. Results support two main conclusions: (1) leaf photosynthetic capacity was unaffected by water stress, and (2) maize effectively endured water shortage during the vegetative growth stage.

LCA of 1,4-Butanediol Produced via Direct Fermentation of Sugars from Wheat Straw Feedstock within a Territorial Biorefinery

The bio-based industrial sector has been recognized by the European Union as a priority area toward sustainability, however, the environmental profile of bio-based products needs to be further addressed. This study investigated, through the Life Cycle Assessment (LCA) approach, the environmental performance of bio-based 1,4-butanediol (BDO) produced via direct fermentation of sugars from wheat straw, within a hypothetical regional biorefinery (Campania Region, Southern Italy). The aim was: (i) to identify the hotspots along the production chain; and (ii) to assess the potential environmental benefits of this bio-based polymer versus the reference conventional product (fossil-based BDO). Results identified the prevailing contribution to the total environmental load of bio-based BDO in the feedstock production and in the heat requirement at the biorefinery plant. The modeled industrial bio-based BDO supply chain, showed a general reduction of the environmental impacts compared to the fossil-based BDO. The lowest benefits were gained in terms of acidification and eutrophication, due to the environmental load of the crop phase for feedstock cultivation.

Measurements of CO2 and N2O Emissions in the Agricultural Field Experiments of the MESCOSAGR Project

Soil organic matter (SOM) under agricultural management is a labile reservoir of C in the planet, and plays a key role in the production and emission to the atmosphere of two main greenhouse gases, CO2 and N2O. This chapter will overview one of the activities of the MESCOSAGR project that is the monitoring of CO2 and N2O emissions from soils under different agronomic treatments. The first part highlights the primary importance at global scale of SOM related to climatic change and agricultural management, including a description of processes involved in the CO2 and N2O evolution from soil. The state of the art of alternative techniques of SOM management in relation to CO2 and N2O emissions is discussed, also on the basis of the scarcity of literature data for Mediterranean croplands. The monitoring system of CO2 and N2O fluxes from field plots of the MESCOSAGR project indicated that compost additions were efficient in reducing fluxes from soils, especially for N2O and for the large compost rates. The role of the compost humified organic matter in exerting a hydrophobic protection against SOM mineralization was thus supported. However, the soil treated with the biomimetic catalyst showed no difference in gases emission from control plots, thereby indicating that the fraction of SOM that was not photo-polymerized continued to be microbially mineralized together with the carbon rhizo-deposited by crop root systems.

N2O Emission Factors for Italian Crops

Nitrous oxide (N2O) emissions from several Italian croplands along a latitudinal gradient were analyzed and the fertilizer induced emission (FIE) factor, for each single fertilization event, was calculated. Data show that the average emission factor was between 0.7 and 0.3 %, hence much lower than the IPCC EF used for temperate croplands. The relationship between N2O production and applied N fertilization rate was exponential and not linear, although the rate of exponential increase was lower than previously reported. Maximum N2O emission rate was correlated with magnitude of the total FIE, whereas it was inversely related to the length of FIE, which varied from a minimum of 8–56 days. Overall data suggest that the internationally applied emission factors for temperate crops, which are empirically derived from sites with cooler and wetter climates than the Mediterranean, would overestimate N2O emissions for Italian crops, in particular those developing between spring and summer.