## 3 Results  
### Soil Parameters  
Significant differences were observed in the mean values of soil chemical variables such as electrical conductivity (EC), total organic carbon (TOC), and soil cations. The results indicate that EC did not differ significantly among the Control, Leachate, and Leachate + Biochar treatments. In contrast, the Biochar treatment increased EC significantly (\(\geq\)1.22 dS m\({}^{-1}\)) compared to all other treatments. Similarly, for TOC, we found that it increased significantly in the treatments that included biochar (Biochar and Leachate + Biochar). A significant difference was observed between the Biochar treatment and both the Leachate and Control treatments, with TOC values at least 0.43% higher in the Biochar treatment. Additionally, a significant difference of 0.35% was found between the Leachate + Biochar and Leachate treatments, as shown in Table 3.  
We analyzed some general groups of microorganisms and indicator genera. Table 4 shows the microbial communities identified in the soil according to the tested treatments. The incorporation of biochar significantly improved the quantity of mesophilic aerobes, molds, and yeasts. Moreover, significant differences (\(\geq\)0.15 and \(\geq\)0.24 log\({}_{10}\)CFU g\({}^{-1}\)) were observed between the Biochar treatment and the Control and Leachate treatments for mesophilic aerobes, respectively. Similarly, molds and yeasts showed significant increases  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Treatment**} & **ECe** & **TN** & **TOC** & **Ca** & **K** & **Na** \\ \cline{2-6}  & **dS m\({}^{-1}\)** & \multicolumn{4}{c}{**Percentage**} & \multicolumn{4}{c}{**cmd kg\({}^{-1}\)**} \\ \hline Control & 4.33 \(\pm\) 1.75 ab & 0.00112 \(\pm\) 0.00046 & 0.734 \(\pm\) 0.095 bc & 8.597 \(\pm\) 0.818 a & 0.539 \(\pm\) 0.201 b & 0.574 \(\pm\) 0.244 ab \\ Leachate & 3.43 \(\pm\) 1.42 b & 0.0009 & 0.684 \(\pm\) 0.098 c & 7.428 \(\pm\) 0.568 bc & 1.044 \(\pm\) 0.253 a & 0.42 \(\pm\) 0.104 b \\ Bochar & 5.85 \(\pm\) 14.44 a & 0.00101 \(\pm\) 0.00035 & 1.16 \(\pm\) 0.38 a & 8.1 \(\pm\) 0.290 ab & 0.688 \(\pm\) 0.040 b & 0.812 \(\pm\) 0.266 a \\ Leachate + Biochar & 3.37 \(\pm\) 1.73 b & 0.00093 \(\pm\) 0.00005 & 1.037 \(\pm\) 0.38 ab & 7.272 \(\pm\) 0.590 c & 0.996 \(\pm\) 0.060 a & 0.382 \(\pm\) 0.174 b \\ \hline \(p\)-value & 0.0136 & 0.3451 & -0.0004 & \textless{}0.0001 & \textless{}0.0001 & \textless{}0.0002 \\ Significance & * & ** & ** & ** \\ \hline \end{tabular} Note: The data in the table express the mean and standard deviation (\(\mu\pm\sigma\)) of the evaluated parameters. Those values with different letters in the same column indicate significant differences between the treatments (\(p<0.05\)), Very highly significant (***), Highly significant (***), Significant (*), Not significant (ns). ECe: Electrical Conductivity in saturation extract, TN: Total Nitrogen, TOC: Total Organic Carbon.  
\end{table}
Table 3: Values of soil chemical parameters.  
(\(\geq\)0.25 and \(\geq\)0.45 log\({}_{10}\) CFU g\({}^{-1}\), respectively) in the Biochar treatment relative to the Control and Leachate treatments, respectively.  
A similar trend was observed in the Leachate + Biochar and Leachate treatment, which also showed increased populations of mesophilic aerobes, molds, and yeasts compared to the Control treatment. The Leachate + Biochar treatment exhibited a significant increase of 0.31 log\({}_{10}\) CFU g\({}^{-1}\) in molds and yeasts relative to the Control.