## 3 Results and Discussion
### Physicochemical Characterization of Soil and Leaf  
Table 2 shows the results obtained in the analysis of the soils treated with organic amendments and of the soil without treatment (control) at the end of the experiment. In the cases studied, pH mean values were determined at 8.10-8.35, which reduce the availability of nutrients for the plant to absorb [53; 54], and mean conductivity values at 0.17-0.80 dS-m\({}^{-1}\), levels remarkably under the threshold of salinity (1.50 dS-m\({}^{-1}\)) referred to in literature for the cultivation of grapevines [55]. It is observed that the treatments with these kinds of organic amendments remarkably increased the presence of organic matter and macronutrients (NO3-, P2O5, K2O) in the soils at the end of the experiment. As per heavy metals, the treatments with the amendments increased the total concentration (Cr, Cu, Ni, Pb) in the soil, although the levels reached (7.7-36.1 mg\(\cdot\)kg\({}^{-1}\)) were significantly under the maximum content allowed in agricultural soils with pH \(\geq\) 7 (70.0 mg\(\cdot\)kg\({}^{-1}\)-200 mg\(\cdot\)kg\({}^{-1}\)), as per Spanish legislation (RD 1051/2022) [22]. With regard to the analysis of the leaves of the grapevine, Table 3 shows the results obtained at the end of the experiment. The physicochemical analysis performed on the leaves showed that the contents of NO3- and K2O were significantly higher with vermicompost compared to the control and compost treatments. These results provide evidence of the relation of the availability of the nutrients in the soil with the application of vermicompost and the variation of the nutritional conditions of the plant, and are consistent with the conclusions of other studies [56]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Property**} & \multicolumn{3}{c}{**Treatment**} & \multirow{2}{*}{**F Test Sig.**} \\ \cline{2-2} \cline{4-4}  & **Control** & **Compost** & & \\ \hline pH & 8.32 a \(\pm\) 0.04 & 8.10 b \(\pm\) 0.01 & 8.10 b \(\pm\) 0.05 & ** \\ EC (dS-m\({}^{-1}\)) & 0.170 b \(\pm\) 0.002 & 0.80 a \(\pm\) 0.02 & 0.74 a \(\pm\) 0.01 & ** \\ OM (\%) & 1.86 c \(\pm\) 0.04 & 2.0 b \(\pm\) 0.2 & 2.7 a \(\pm\) 0.1 & * \\ NO3- (\%) & 0.027 b \(\pm\) 0.001 & 0.161 a \(\pm\) 0.005 & 0.17 a \(\pm\) 0.02 & * \\ P2O5 (\%) & 0.09 b \(\pm\) 0.01 & 0.30 a \(\pm\) 0.02 & 0.30 a \(\pm\) 0.01 & * \\ K2O (\%) & 0.005 c \(\pm\) 0.001 & 0.119 b \(\pm\) 0.007 & 0.181 a \(\pm\) 0.007 & * \\ Cr (mg/kg) & 2.2 c \(\pm\) 0.2 & 11.5 a \(\pm\) 0.3 & 7.7 b \(\pm\) 0.1 & ** \\ Cu (mg/kg) & 2.3 c \(\pm\) 0.1 & 17.0 b \(\pm\) 0.8 & 22 a \(\pm\) 1 & * \\ Ni (mg/kg) & 6.1 c \(\pm\) 0.4 & 26 b \(\pm\) 1 & 36 a \(\pm\) 2 & ** \\ Pb (mg/kg) & 11.6 c \(\pm\) 0.3 & 33.1 a \(\pm\) 0.9 & 20 b \(\pm\) 1 & * \\ Zn (mg/kg) & \textless{}LOQ(20) & \textless{}LOQ(20) & \textless{}LOQ(20) & - \\ \hline \hline \end{tabular} Data expressed in dry weight basis. EC: electrical conductivity; OM: organic matter; LOQ: limit of quantification. Different letters indicate significant differences (* \(p<\) 0.05, ** \(p<\) 0.01, ** \(p<\) 0.001), ns = non-significant. (–) No test was performed.  
\end{table} 
Table 2: Soil properties at the end of the experiment.