## 3 Results and Discussion
### Physical Properties  
Table 6 summarizes the physical properties of the biochars. The porosity increased with pyrolysis duration for both the broom- and gorse-derived biochars. The highest porosity for broom-derived biochars was recorded for BB600-3H and for BG600-1H for gorse-derived biochars. The V mesoporosity increased in the broom-derived biochars with pyrolysis temperature. On the contrary, the V mesoporosity in gorse-derived biochars produced at 300 \({}^{\circ}\)C was lower than that of the feedstock but higher that of the biochars produced at 600 \({}^{\circ}\)C. The V macroporosity was higher in biochars than in the feedstock (broom and gorse).  
\begin{table}
\begin{tabular}{c c c c c} \hline  & **C\({}_{\text{oxi}}\) (\%)** & **pH** & **EC (\(\upmu\)S cm\({}^{-1}\))** & **WEOC (mg kg\({}^{-1}\))** \\ \hline BROOM & 44.36 \(\pm\) 0.76 c & 5.65 \(\pm\) 0.04 a & 218.67 \(\pm\) 18.01 c & 67,196.37 \(\pm\) 1882.12 c \\ BB300-1H & 45.78 \(\pm\) 0.82 c & 8.56 \(\pm\) 0.31 b & 95 \(\pm\) 3.96 b & 4671.04 \(\pm\) 131.73 b \\ BB300-3H & 39.12 \(\pm\) 1.09 b & 8.90 \(\pm\) 0.19 c & 75.27 \(\pm\) 2.74 a & 1086.64 \(\pm\) 9.68 a \\ BB600-1H & 1.31 \(\pm\) 0.9 a & 9.53 \(\pm\) 0.15 d & 215.33 \(\pm\) 2.52 c & 777.77 \(\pm\) 22.35 a \\ BB600-3H & 2.17 \(\pm\) 0.44 a & 9.52 \(\pm\) 0.11 d & 263 \(\pm\) 8.54 d & 1001.02 \(\pm\) 44.59 a \\ \hline GORSE & 42.95 \(\pm\) 1.21 B & 6.48 \(\pm\) 0.14 A & 108.8 \(\pm\) 1.7 B & 31,396.85 \(\pm\) 187.82 D \\ BG300-1H & 47.24 \(\pm\) 1.32 C & 8.28 \(\pm\) 0.03 B & 104.25 \(\pm\) 2.95 A,B & 3619.17 \(\pm\) 44.23 C \\ BG300-3H & 41.2 \(\pm\) 1.79 B & 9.59 \(\pm\) 0.17 C & 100.23 \(\pm\) 1.69 A & 735.52 \(\pm\) 15.29 B \\ BG600-1H & 5.88 \(\pm\) 0.35 A & 10.42 \(\pm\) 0.12 D & 233.67 \(\pm\) 4.16 D & 510.38 \(\pm\) 19.54 A \\ BG600-3H & 6.32 \(\pm\) 0.19 A & 10.32 \(\pm\) 0.04 D & 209.5 \(\pm\) 4.5 C & 449.66 \(\pm\) 20.86 A \\ \hline \end{tabular}
\end{table}
Table 5: C\({}_{\text{oxi}}\), pH, EC, and WEOC (dry basis) for broom, gorse, and their respective biochars. Means with the same letter are not significantly different (\(p\) > 0.05) according to [PERSON]’s test for broom (lower case) and gorse (upper case) independently.  
The bulk density presented the highest values for broom and gorse feedstock; instead, the solid density was the highest for the biochars fabricated at 600 \({}^{\circ}\)C. These data are consistent with the presence of more pores at low pyrolysis temperatures than in solids. The total porosity of the broom materials support the aforementioned behavior, with higher values found for the biochars produced at 300 \({}^{\circ}\)C. For the gorse-derived materials, the total porosities for all biochars were similar but higher than those of the gorse.  
[PERSON] et al. [89] reported a similar solid density for species of the Fabaceae family, specifically, black locust, eastern redbud, and honey locust, with values of 1.57, 1.72, and 1.82 g cm\({}^{-3}\), respectively. Another investigation of woody biomass reported a bulk density of 0.73 g cm\({}^{-3}\) and specific gravity density of 1.36 g cm\({}^{-3}\)[90]. Those data are comparable to the present results (Table 6), with our values being within the ranges. Regarding the porosity and V mesoporousity, the trends were the same as those in other investigations [91], where the increase in pyrolysis temperature led to a more developed pore structure.