# Feasibility of Utilizing Biodegradable Plastic Film to Cover Corn Silage under Farm Conditions
## Results
### Fermentative Profile  
The pH evolution in corn silage, as affected by the time of conservation, the distance from the plastic film and the type of plastic cover, is reported in Figure 1. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Data** & **Mean T** & **Max T** & **Min T** \\ \hline Ensiling & 7 Sept & 18.9 & 27.4 & 13.1 \\
21 d & 28 Sept & 17.8 & 27.6 & 10.5 \\
85 d & 01 Dec & 4.5 & 12.0 & –0.4 \\
133 d & 18 Jan & –3.4 & 2.3 & –7.2 \\
185 d & 10 Mar & 5.7 & 14.1 & –1.6 \\
230 d & 24 Apr & 13.7 & 21.2 & 7.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Ambient temperature (\({}^{\circ}\)C) during the experimental period. Figure 1: The pH evolution in corn silage, as affected by the time of conservation and the type of plastic cover. Means with a different lowercase letter in the table, within the same column, are different; means with a different uppercase letter in the same row are different. The values at ensiling were not included in the statistical analysis. The pH decreased from ensiling to 133 days of conservation in all the silages. After 133 days, MB-CF showed a rapid increase in pH, which reached 6.26 at 230 days of conservation. The pH in the silages covered with PE and OB plastic films started to increase after 185 days of conservation, that is, when the temperature started to increase in spring. The pH was higher in the CF areas than in the FF areas, regardless of the type of plastic cover. The MB film showed a pH increase in the peripheral areas after 133 d. The OB cover determined the lowest values of pH in both the CF and FF areas. The lactic, acetic and propionic acid evolutions in corn silage, as affected by the time of conservation and the type of plastic cover, are reported in Figures 2-4, respectively. Lactic acid increased in the FF areas until 133 days of conservation, regardless of the type of plastic cover, and then remained constant. However, the CF areas showed lower lactic acid values than the FF areas. Lactic acid decreased significantly in the MB-CF and PE-CF films after 133 and 185 days of conservation, respectively. Acetic acid greatly increased in the FF areas after 85 days of conservation. A similar trend was observed in PE-CF and OB-CF, albeit with higher values. The MB-CF showed the greatest increase in acetic acid until 133 days of conservation, after which it quickly decreased, consistently with the propionic acid content trend. No practical differences were observed in the propionic acid content at 21 and 85 days of ensiling between PE, OB and MB-FF. The ethanol evolution in the corn silage is reported in Figure 5. The ethanol content in the FF areas was typical of corn silage harvested at 40% DM, with values of around 16 g/kg DM. OB-CF showed the highest value of ethanol (up to 20 g/kg DM) until 133 days of conservation, and it decreased after a longer conservation period. The ethanol content in MB-CF decreased significantly after 85 days of ensiling, and it was under the detection limit at 230 days. Figure 2: Lactic acid evolution in corn silage, as affected by the time of conservation and the type of plastic cover. Means with a different lowercase letter in the table, within the same column, are different; means with a different uppercase letter in the same row are different. The values at ensiling were not included in the statistical analysis. Figure 4: Propionic acid evolution in the corn silage, as affected by the time of conservation and the type of plastic cover. Means with a different lowercase letter in the table, within the same column, are different; means with a different uppercase letter in the same row are different. The values at ensiling were not included in the statistical analysis. Figure 3: Acetic acid evolution in the corn silage, as affected by the time of conservation and the type of plastic cover. Means with a different lowercase letter in the table, within the same column, are different; means with a different uppercase letter in the same row are different. The values at ensiling were not included in the statistical analysis.