# Popular Biochar as an Alternative Substrate for Curly Endive Cultivated in a Soilless System
## 3 Results
### Nutritional and Functional Properties
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Treatments** & **N (mg g\({}^{-1}\) DW)** & **P (mg g\({}^{-1}\) DW)** & **K (mg g\({}^{-1}\) DW)** & **Ca (mg g\({}^{-1}\) DW)** & **Mg (mg g\({}^{-1}\) DW)** \\ \hline Peat (PE) & \(6.42\pm 0.11\) & a & \(0.63\pm 0.03\) & a & \(2.92\pm 0.03\) & f & \(0.75\pm 0.03\) & b & \(0.37\pm 0.01\) & a \\ Biochar 20\%\_450 (BC24) & \(4.85\pm 0.10\) & b & \(0.63\pm 0.01\) & a & \(3.07\pm 0.06\) & e & \(0.68\pm 0.02\) & cd & \(0.35\pm 0.02\) & a \\ Biochar 20\%\_700 (BC27) & \(6.66\pm 0.08\) & bc & \(0.62\pm 0.01\) & a & \(3.21\pm 0.02\) & d & \(0.82\pm 0.02\) & a & \(0.35\pm 0.01\) & a \\ Biochar 40\%\_450 (BC44) & \(4.4\pm 0.13\) & cd & \(0.63\pm 0.03\) & a & \(3.30\pm 0.06\) & d & \(0.62\pm 0.02\) & ef & \(0.35\pm 0.01\) & a \\ Biochar 40\%\_700 (BC47) & \(4.27\pm 0.10\) & de & \(0.62\pm 0.03\) & a & \(3.44\pm 0.02\) & c & \(0.72\pm 0.02\) & bc & \(0.35\pm 0.01\) & a \\ Biochar 70\%\_450 (BC47) & \(4.13\pm 0.08\) & e & \(0.62\pm 0.03\) & a & \(3.65\pm 0.03\) & b & \(0.55\pm 0.03\) & g & \(0.33\pm 0.01\) & a \\ Biochar 70\%\_700 (BC77) & \(3.81\pm 0.10\) & f & \(0.62\pm 0.01\) & a & \(3.71\pm 0.03\) & b & \(0.62\pm 0.01\) & de & \(0.36\pm 0.01\) & a \\ Biochar 100\%\_450 (BC14) & \(3.52\pm 0.08\) & g & \(0.64\pm 0.02\) & a & \(3.87\pm 0.02\) & a & \(0.42\pm 0.03\) & h & \(0.35\pm 0.01\) & a \\ Biochar 100\%\_700 (BC17) & \(3.23\pm 0.12\) & h & \(0.64\pm 0.03\) & a & \(3.96\pm 0.02\) & a & \(0.56\pm 0.02\) & fg & \(0.35\pm 0.02\) & a \\ \hline Significance & *** & \multicolumn{3}{c}{NS} & *** & *** & \multicolumn{3}{c}{NS} \\ \hline \multicolumn{7}{l}{The same letter within a column identifies data (mean \(\pm\) standard deviation) not significantly different (\(p\leq 0.05\) Tukey HSD Test). Asterisks (***) are designated for the significance (\(p\)-value \(\leq 0.001\)).} \\ \end{tabular}
\end{table} 
Table 5: Analysis of variance and means comparisons for leaves N, P, K, Ca and Mg content of curly entive cultivated on different growing substrates in a protected environment. which in turn showed values higher than plants grown on biochar at 20% with a pyrolysis temperature of 700 \({}^{\circ}\)C. However, ANOVA, did not reveal statistical significant differences between biochar at 20% with a pyrolysis temperature of 450 \({}^{\circ}\)C and biochar at 20% with a pyrolysis temperature of 700 \({}^{\circ}\)C in terms of N leaf content. The lowest leaf N content was detected in plants from biochar 100% with a pyrolysis temperature of 700 \({}^{\circ}\)C.  
Plants cultivated on 100% biochar growing substrates produced both with a pyrolysis temperature of 450 and 700 \({}^{\circ}\)C had the highest values in terms of leaves K content, followed by those grown on substrate mixtures with 70% of biochar (both produced with a pyrolysis temperature of 450 or 700 \({}^{\circ}\)C). Plants from plots with 100% peat revealed the lowest leaves K values. However, in general, K concentration increased with the increase of biochar content. The highest leaves Ca contents were observed in plants grown on biochar at 20% with a pyrolysis temperature of 700 \({}^{\circ}\)C, while the lowest values were detected in plants grown on biochar at 100% with a pyrolysis temperature of 450 \({}^{\circ}\)C.