## 2 Materials and Methods
### Life Cycle Inventory (LCI)  
The life cycle inventory analysis is the process of data collection and analysis aiming at quantifying the resource inputs, the energy consumption, and the environmental outputs to take into account in the life cycle of a product [41; 42]. Primary data include detailed information on the maize cultivation and are based on the interviews with the farmers. Primary data related to corn cob production were not available for the study and therefore have been calculated from maize grain production, considering literature parameters. In fact, the corn cob production quantities have been obtained for the areas under consideration starting from the data on maize grain production. Average data on maize grain and corn cob productions (t/ha), referred to the geographical area of the Northern Italy, have been extracted from [43] and summarized in Table 3.  
Since the cob, on average, represents 15% of the weight of an ear corn when harvested, in the hypothesis of a grain production about 15 t/ha, a potential harvest of 3 t/ha of cob (42% humidity) is expected, with a ratio between the two products (based on the dry matter) of 11.6 [43]. In this study, the maize grain production have been estimated by primary data of 14.2 t/ha. Literature data are available for the production of maize corn cobs based on dry matter values, as visible in Table 3.  
\begin{table}
\begin{tabular}{c c c c c c} \hline  & & & & & \\ \hline
**Year** & **Total** & **Waxy** & **(\%)** & **Grain** & **(\%)** \\ \hline
2017 & 573,407 & 277,909 & 48.47 & 295,498 & 51.53 \\
2018 & 518,524 & 287,482 & 55.44 & 230,942 & 44.53 \\
2019 & 556,782 & 299,663 & 53.82 & 257,119 & 46.18 \\ \hline  & & & & & \\ \hline
**Year** & **Total** & **Waxy** & **(\%)** & **Grain** & **(\%)** \\ \hline
2017 & 645,261 & 342,101 & 53.02 & 303,160 & 46.98 \\
2018 & 591,206 & 355,527 & 60.1 & 235,879 & 39.9 \\
2019 & 628,801 & 367,422 & 58.43 & 261,379 & 41.57 \\ \hline \end{tabular}
\end{table}
Table 1: Area dedicated to maize cultivation in hectares (ha): (**a**) Northern Italy (Lombardy, Veneto, Piedmont, Emilia-Romagna, (**b**) Italy.  
\begin{table}
\begin{tabular}{c c c} \hline
**Provinces** & **Dedicated Surfaces (ha)** & **Annual Production (t)** \\ \hline Belluno & 1522 & 1100.89 \\ Padua & 36,356 & 30,992.9 \\ Rovigo & 34,568 & 30,449.8 \\ Treviso & 21,867 & 21,126.8 \\ Venice & 30,702 & 30,314 \\ Verona & 25,790 & 22,532.5 \\ Vicenza & 14,547 & 12,996.55 \\ \hline \end{tabular}
\end{table}
Table 2: Data of maize production (t) and dedicated surfaces (ha) of the Provinces of the Veneto Region.  
Data on water consumption for irrigation have been assumed from literature, based on rain precipitation data. The impoverishment of soil nutrients due to the lack in the field of the corn cob, even limited, has been taken into account, on the basis of literature data. In the study [19], this impoverishment has been modeled and quantified, in order to be considered in the LCA analysis, in grain and the cob corn production phase as avoided emissions to soil (see Table 4).  
Life cycle inventory data, input and output, for the production of corn cob pellets and corn cob grits have been obtained from the literature. Finally, for the production of wood pellets and silicon carbide, the processes available in the database Ecoinvent 3.6 have been considered. For the modeling of flows and processes, the software OpenLCA 1.10.2 has been used.