## 3 Results
### GHG Emissions  
The addition of digestates to soil led to a significant increase in CO\({}_{2}\) emissions (Figure 2, top), without differences between the two tested samples. Biochar showed a contrasting, dose dependent pattern: a significant increase at the lower concentration of 2% and a reduction with 10%, which lowered the CO\({}_{2}\) production to the level of control soil (Table 6).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{_Lactuca sativa_} & \multicolumn{2}{c}{_Triticum aestivum_} \\
**Factor** & **F Value** & **_p\textless{}_** & **F Value** & **_p\textless{}_** \\ \hline Treatment & 54.9 & 0.001 & 18.1 & 0.001 \\ Dilution & 6.0 & 0.01 & 0.5 & n.s. \\ treatment \(\times\) dilution & 5.8 & 0.001 & 1.2 & n.s. \\ \hline \hline \end{tabular}
\end{table}
Table 4: Germination index two-way ANOVA results for _L. sativa_ (lettuce) and _T. aestivum_ (wheat) seeds according to the different EOMs added to soil (treatment), dilution ratio (dilution), or their interaction (treatment \(\times\) dilution); n.s. = not statistically significant.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Treatment** & **TC (\%)** & **TOC (\%)** & **TN (\%)** & **C/N** & **pH** & **EC (dS/m)** \\ \hline Control & 1.45 (0.02) b & 0.69 (0.01) d & 0.11 (0.002) e & 13.4 (0.3) a & 7.91 (0.04) ab & 30.9 (2.8) c \\ Dig1 & 1.50 (0.05) b & 0.78 (0.01) d & 0.13 (0.002) de & 11.9 (0.2) bc & 8.00 (0.02) a & 28.5 (0.8) c \\ Dig2 & 1.59 (0.06) b & 0.79 (0.02) cd & 0.14 (0.001) cde & 11.5 (0.5) c & 7.93 (0.03) ab & 26.9 (1.6) c \\ Bio2\% & 1.90 (0.01) b & 1.31 (0.01) bcd & 0.15 (0.003) bcd & 12.3 (0.3) abc & 7.87 (0.03) bc & 27.1 (1.3) d \\ Bio10\% & 4.89 (0.66) a & 4.24 (0.51) a & 0.38 (0.035) a & 12.9 (0.7) ab & 7.81 (0.01) cd & 49.3 (4.9) a \\ Dig1+bio2\% & 2.15 (0.12) b & 1.47 (0.17) bc & 0.17 (0.010) bc & 12.4 (0.1) abc & 7.93 (0.02) ab & 29.6 (1.7) c \\ Dig2+bio2\% & 2.15 (0.13) b & 1.63 (0.24) b & 0.18 (0.016) b & 11.7 (0.4) c & 7.94 (0.03) ab & 34.1 (2.5) c \\ Dig1+bio10\% & 4.31 (0.20) a & 3.68 (0.21) a & 0.34 (0.015) a & 12.7 (0.1) abc & 7.78 (0.05) d & 61.6 (3.4) b \\ Dig2+bio10\% & 4.46 (0.38) a & 3.92 (0.29) a & 0.34 (0.013) a & 13.3 (0.7) a & 7.82 (0.02) cd & 61.7 (3.4) b \\ \hline \hline \end{tabular}
\end{table}
Table 5: Chemical properties of soil at the end of mesocosom experiments (standard errors in parenthesis). Different letters indicate significant differences at \(p\) < 0.05 ([PERSON]’s least Significant Difference, LSD). Bio, biochar; Dig1, digestate from reactor 1; Dig2, digestate from reactor 2.  
Overall, CH\({}_{4}\) uptake was prevalent throughout the incubation period (Figure 2, middle), with values around 0 after 2 weeks in samples with digestate + biochar. Digestate addition reduced CH\({}_{4}\) uptake, likewise the biochar at the highest concentration (10%). Biochar at 2% concentration did not differ from control soils (Table 6).  
N\({}_{2}\)O production (Figure 2, bottom) was minimum for control soils and increased significantly with digestate addition and with biochar at the highest concentration of 10% (Table 6). The combination of digestate + biochar showed contrasting results depending on biochar concentration, with a decrease to control values with 2% and a sharp increase (around 3 times higher that digestate alone) with 10% of biochar.  
Figure 2: Potential production/consumption of CO\({}_{2}\) (**top**), CH\({}_{4}\) (**middle**) and N\({}_{2}\)O (**bottom**) in control soils, and after addition of digestate R1 and R2 (Dig1 and Dig2) and/or 2% and 10% of biochar (Dig1+bio2%, Dig2+bio2%, Dig1+bio10%, Dig2+bio10%) during the 22 days of incubation. Error bars calculated as standard errors in replicate mesocosoms.