# Evaluation of Conifer Wood Biochar as Growing Media Component for Citrus Nursery
## 3 Results and Discussions
### Chemical and Physical Properties of Growth Media
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Grouping** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** & **Container** \\
**a** & **Weight Gap** & **Bulk Density (g cm\({}^{-9}\)) & **Water Field Sturation (\%)** & **Water Content at Field Capacity (\%)** & **Water Content at Field Capacity (\%)** & **Water Content at Field** & **Container** & **Container** & **Container** & **Container** \\ \hline
**A** & 62.4 \(\pm\) 0.27 B & 0.73 \(\pm\) 0.05 AB & 0.72 \(\pm\) 0.10 a & 38.76 \(\pm\) 1.49 B & 41.02 \(\pm\) 4.30 & 10.27 \(\pm\) 2.73 BC & 20.01 \(\pm\) 0.16 BC & 15.94 \(\pm\) 0.26 BC & 14.46 \(\pm\) 1.57 & 3.76 \(\pm\) 2.82 B & 55.85 \(\pm\) 1.35 BC \\
**B** & 63.5 \(\pm\) 0.31 B & 0.43 \(\pm\) 0.11 AB & 0.48 \(\pm\) 0.08 & 43.58 \(\pm\) 2.74 A & 45.83 \(\pm\) 0.61 & 25.71 \(\pm\) 1.32 BC & 25.47 \(\pm\) 1.33 BC & 15.85 \(\pm\) 1.10 & 14.41 \(\pm\) 1.36 BC & 1.16 \(\pm\) 1.54 A & 1.29 \(\pm\) 0.25 A \\
**C** & 63.2 \(\pm\) 0.46 AB & 0.44 \(\pm\) 0.14 AB & 0.64 \(\pm\) 0.48 AB & 43.15 \(\pm\) 1.43 AB & 44.45 \(\pm\) 3.47 & 20.77 \(\pm\) 1.54 BC & 21.86 \(\pm\) 0.55 AB & 15.08 \(\pm\) 0.08 & 15.362 \(\pm\) 1.02 & 4.04 \(\pm\) 0.38 AB & 2.83 \(\pm\) 0.41 AB \\
**D** & 63.5 \(\pm\) 0.30 AB & 0.56 \(\pm\) 0.10 AB & 0.68 \(\pm\) 0.03 & 47.78 \(\pm\) 0.16 & 4.05 \(\pm\) 2.89 & 2.296 \(\pm\) 0.45 AB & 23.15 \(\pm\) 0.58 AB & 17.17 \(\pm\) 0.53 AB & 17.07 \(\pm\) 0.52 AB & 2.07 \(\pm\) 0.52 AB & 2.05 \(\pm\) 0.78 AB \\
**E** & 65.2 \(\pm\) 0.43 B/ 0.84 \(\pm\) 0.12 A & 0.58 \(\pm\) 0.05 & 40.50 \(\pm\) 4.49 \(\pm\) 0.20 BC & 44.95 \(\pm\) 0.20 BC & 22.47 \(\pm\) 1.18 BC & 15.94 \(\pm\) 0.44 & 14.53 \(\pm\) 0.39 & 5.90 \(\pm\) 0.32 AB & 7.93 \(\pm\) 0.22 AB \\
**F** & 63.2 \(\pm\) 0.13 A, 0.44 \(\pm\) 0.14 AB & 0.69 \(\pm\) 0.05 & 44.00 \(\pm\) 4.48 AB & 44.32 \(\pm\) 3.24 & 17.14 \(\pm\) 1.74 BC & 15.79 \(\pm\) 0.52 BC & 15.96 \(\pm\) 2.61 & 14.99 \(\pm\) 0.67 & 5.17 \(\pm\) 0.61 BC \\
**G** & 59.4 \(\pm\) 0.08 B & 0.46 \(\pm\) 0.07 B & 0.57 \(\pm\) 0.040 & 45.72 \(\pm\) 0.68 & 24.46 \(\pm\) 4.46 BC & 16.33 \(\pm\) 1.41 C & 17.82 \(\pm\) 1.35 BC & 14.92 \(\pm\) 6.67 & 12.55 \(\pm\) 1.46 & 2.65 \(\pm\) 1.45 B & 2.69 \(\pm\) 1.46 \\ \hline \end{tabular}
\end{table} 
Table 2: Container weight, bulk density, and hydrological properties of growing media recorded at the start (November 2013) and end (October 2015) of the trial. Values are means (standard deviation). Values in a column indicated by different letters are significantly different (lowercase \(p<0.05\), uppercase \(p<0.001\)) based on [PERSON]’s HSD test. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Growing Medium 1 ** & **Total Porosity (vol \%)** & **Air Space (vol \%)** & **Water Filled Porosity (vol \%)** \\ \hline  & **Start** & **End** & **Start** & **End** & **Start** & **End** \\ \hline A & 28.65 \(\pm\) 1.99 & 18.73 \(\pm\) 1.59 & 21.03 \(\pm\) 2.00 ab & 12.94 \(\pm\) 1.36 A & 8.62 \(\pm\) 1.21 ab & 5.80 \(\pm\) 0.23 B \\ B & 28.22 \(\pm\) 0.69 & 19.09 \(\pm\) 1.31 & 18.18 \(\pm\) 3.27 b & 11.01 \(\pm\) 0.90 AB & 10.04 \(\pm\) 2.59 a & 8.08 \(\pm\) 0.46 AB \\ C & 27.560 \(\pm\) 1.95  
The carbon/nitrogen (C:N) ratio was always below 4.2 (B) (not reported). These values indicate improved N availability, resulting in a net release of N into the substrate solution and, consequently, offering the opportunity to reduce the fertilization rate. A too-high (C:N) ratio can result in N immobilization [35]. Before potting the different mixtures showed variable pH values according to their composition. The starting pH ranged from 4.66 (G) to 7.56 (F) (Table 1). The E and F compost mixture and that containing 50% biochar (B) had a significantly higher pH than A and G. Only C and D had a pH suitable for citrus and mainly the Carrizo citrange rootstock examined here [36].