## 3 Results
### Water Use Efficiency  
In contrast, as illustrated in Table 4 and Figure 2, the obtained WUE (computed by dividing the tomato fruit yield (kg m\({}^{-2}\)) with the amount of nutrient solution utilized for irrigation in m\({}^{3}\) m\({}^{-2}\)) of the tomato crops varied significantly across the salinity treatments. The highest WUE (31.3 kg m\({}^{-3}\)) was recorded under the low-salinity conditions (S1), and the value was low under the high-salinity conditions (S3). These findings agree with [PERSON] et al. [28], who found that the WUE of eggplant increased with increasing salinity stress. These results imply that tomato plants can perform better under low-salinity (S1) to moderate-salinity (S2) conditions, and that it is viable to utilize low to moderate saline water in a proportion of the nutrient solution as irrigation water in hydroponics to improve WUE [29]. This study also confirmed that moderate saline water is an alternative for tomato production under hydroponic conditions throughout a growing season to achieve an acceptable yield (31.3-30.4 kg m\({}^{2}\)). \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Treatments**}} & \multicolumn{3}{c}{**Plant Height (cm)**} & \multicolumn{3}{c}{**Stem Diameter (mm)**} & \multicolumn{3}{c}{**Leaf Area (m\({}^{2}\) plant\({}^{-1}\))**} \\ \cline{2-10}  & **Season 1** & **Season 2** & **Mean** & **Season 1** & **Season 2** & **Mean** & **Season 1** & **Season 2** & **Mean** \\ \hline \multicolumn{10}{l}{(a) Salinity level} \\ S1 (-2.5 dS m\({}^{-1}\)) & 188.5 \({}^{\mathrm{a}}\) & 198.7 \({}^{\mathrm{a}}\) & 193.6 & 13.7 \({}^{\mathrm{a}}\) & 14.1 \({}^{\mathrm{a}}\) & 13.9 & 15.9 \({}^{\mathrm{a}}\) & 16.0 \({}^{\mathrm{a}}\) & 16.0 \\ S2 (-6.0 dS m\({}^{-1}\)) & 179.7 \({}^{\mathrm{a}}\) & 166.9 \({}^{\mathrm{b}}\) & 173.3 & 12.3 \({}^{\mathrm{b}}\) & 13.1 \({}^{\mathrm{a}}\) & 12.7 & 14.8 \({}^{\mathrm{b}}\) & 15.9 \({}^{\mathrm{b}}\) & 15.4 \\ S3 (-9.0 dS m\({}^{-1}\)) & 124.1 \({}^{\mathrm{b}}\) & 129.6 \({}^{\mathrm{c}}\) & 126.9 & 10.6 \({}^{\mathrm{c}}\) & 9.8 \({}^{\mathrm{b}}\) & 10.2 & 11.0 \({}^{\mathrm{c}}\) & 11.8 \({}^{\mathrm{c}}\) & 11.4 \\ \multicolumn{10}{l}{(b) Nutrient recipe} \\ N1 (control & 173.0 \({}^{\mathrm{a}}\) & 169.6 \({}^{\mathrm{a}}\) & 171.3 & 12.1 \({}^{\mathrm{a}}\) & 12.7 \({}^{\mathrm{a}}\) & 12.4 & 14.2 \({}^{\mathrm{a}}\) & 14.7 \({}^{\mathrm{a}}\) & 14.5 \\ N2 (N1 + 15\% K) & 166.0 \({}^{\mathrm{a}}\) & 176.1 \({}^{\mathrm{a}}\) & 190.1 & 12.2 \({}^{\mathrm{a}}\) & 12.8 \({}^{\mathrm{a}}\) & 12.5 & 14.3 \({}^{\mathrm{a}}\) & 14.8 \({}^{\mathrm{a}}\) & 14.6 \\ N3 (N1 + 15\% Ca) & 160.4 \({}^{\mathrm{b}}\) & 153.3 \({}^{\mathrm{b}}\) & 156.9 & 11.6 \({}^{\mathrm{b}}\) & 12.6 \({}^{\mathrm{a}}\) & 12.2 & 13.4 \({}^{\mathrm{b}}\) & 14.9 \({}^{\mathrm{a}}\) & 14.2 \\ N4 (N1 + 15\% K + Ca) & 157.0 \({}^{\mathrm{b}}\) & 161.3 \({}^{\mathrm{b}}\) & 159.2 & 11.4 \({}^{\mathrm{b}}\) & 12.1 \({}^{\mathrm{b}}\) & 11.8 & 13.7 \({}^{\mathrm{b}}\) & 13.8 \({}^{\mathrm{b}}\) & 13.8 \\ \multicolumn{10}{l}{(c) Grafting} \\ GR (Grafted) & 179.3 \({}^{\mathrm{a}}\) & 173.9 \({}^{\mathrm{a}}\) & 176.3 & 13.3 \({}^{\mathrm{a}}\) & 13.6 \({}^{\mathrm{a}}\) & 13.5 & 15.1 \({}^{\mathrm{a}}\) & 15.7 \({}^{\mathrm{a}}\) & 15.4 \\ NG (Non-grafted) & 149.1 \({}^{\mathrm{b}}\) & 156.2 \({}^{\mathrm{b}}\) & 152.6 & 10.4 \({}^{\mathrm{b}}\) & 11.6 \({}^{\mathrm{b}}\) & 11.0 & 12.6 \({}^{\mathrm{b}}\) & 13.5 \({}^{\mathrm{b}}\) & 13.1 \\ \multicolumn{10}{l}{(d) Tomato cultivars} \\ Valouro-RZ & 154.8 \({}^{\mathrm{c}}\) & 156.5 \({}^{\mathrm{c}}\) & 155.7 & 11.4 \({}^{\mathrm{b}}\) & 12.1 \({}^{\mathrm{b}}\) & 11.8 & 133.6 \({}^{\mathrm{b}}\) & 138.9 \({}^{\mathrm{c}}\) & 136.3 \\ \multicolumn{10}{l}{(Ghandowa-F1} \\ \multicolumn{10}{l}{(Fisty-Red} \\ \hline \hline \end{tabular} Note: The values with different superscript letters in a column are significantly different (\(p<0.05\)).  
\end{table} 
Table 3: Responses of tomato crops grown under different salinity and nutrient treatments.