# Biochar Improved Sugarcane Growth and Physiology under Salinity Stress
## 3 Results  
### Effects of Salinity and Biochar Application on sugarcane Growth Responses  
Salinity and biochar application significantly affected sugarcane plant growth characteristics including plant height and stem diameter (Figure 1). Although plant height and stem diameter still increased by week, those under salinity conditions were smaller than those under non-salinity. Applying biochar showed an effect in reducing the impact of saline stress on the growth of sugarcane. The differences in plant height and stem diameter of plants between control (non-salinity) and salinity were found to be smallest when applying biochar with 10 tons-ha\({}^{-1}\), followed by 5 tons-ha\({}^{-1}\). Plants without biochar application were recorded with the most severe impact of the salinity condition, as shown by the largest reduction in both plant height and stem diameter (Figure 1).  
The saline stress decreased the dry biomasses of stems, leaves, and roots of sugarcane (Table 2). On the final salinity treatment day, the dry biomasses of leaves and roots did not significantly vary among plants growing under non-saline and saline conditions (6.43 and 6.11 g plant\({}^{-1}\) for leaf dry biomass, respectively; 1.92 and 1.82 g plant\({}^{-1}\) for root dry biomass, respectively). However, significant differences with non-salinity were observed for all dry biomass measurements at 4 weeks after the salinity treatment day. Biochar had significantly positive effects on dry biomasses of stems, leaves, and roots of sugarcane, with the highest values observed in plants applied with 10 tons of biochar ha\({}^{-1}\) (Table 2). On the final salinity treatment day, dry biomasses of stems, leaves, and roots of sugarcane without salinity at 10 tons ha\({}^{-1}\) of biochar were 4.39, 7.45, and 2.40 g plant\({}^{-1}\), respectively, while those at 5 tons ha\({}^{-1}\) were 3.81, 6.29, and 1.72 g plant\({}^{-1}\), respectively. Similarly, after 4 weeks of final salinity treatment day, dry biomasses of stems, leaves, and roots of sugarcane were also highest with values of 7.33, 8.23, and 2.63 g plant\({}^{-1}\), respectively, at the application rate of 10 tons of biochar ha\({}^{-1}\). There was no significant interaction between saline and biochar application for the growth parameters of sugarcane plants.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Salinity Treatment**} & **Biochar** & \multicolumn{3}{c}{**Final Salinity Treatment Day**} & \multicolumn{3}{c}{**4 Weeks after the Final Salinity Treatment Day**} \\ \cline{3-8}  & **Application** & **Stem** & **Leaves** & **Root** & **Stem** & **Leaves** & **Root** \\  & **(tons ha\({}^{-1}\))** & **(g plant\({}^{-1}\))** & **(g plant\({}^{-1}\))** & **(g plant\({}^{-1}\))** & **(g plant\({}^{-1}\))** & **(g plant\({}^{-1}\))** & **(g plant\({}^{-1}\))** \\ \hline \multirow{3}{*}{Non-salinity} & 0 & 3.76 b \({}^  
Figure 1: Plant height and stem diameter of sugarcane in response to salinity treatments under 0, 5, and 10 toes of biochar ha\({}^{-1}\). Vertical bars represent mean \(\pm\) SD, \(n=12\). Significance levels (\(n\)-test): ns: non-significant; \(n>0.05\); \(n>0.01\); \(n>0.001\).  
Biochar application also increased root volume with the highest values recorded at the rate of 10 tons ha\({}^{-1}\) under both non-saline and saline conditions (Figure 2). There was no significant difference in root volume on the final day of salinity treatment (14 days) between non-salinity and salinity at the same biochar application level (Figure 2A). However, the effects of salinity were seen after 4 weeks of final salinity treatment as a significant decrease in root volume was observed in the salinity treatment compared with non-salinity treatment (Figure 2B).