# Evaluation of Conifer Wood Biochar as Growing Media Component for Citrus Nursery
## 3 Results and Discussions  
### Chemical and Physical Properties of Growth Media  
The main chemical and physical properties of the growing media are listed in Tables 1-3. As can be seen, different parameters modify significantly in the trial. In Table 1, D, E, and F show a significant and higher value of N than A and C. However, all growing media showed similar values to those reported with composted pine bark [33]. The organic matter (OM) content was very low according to [PERSON] and co-workers [34]. In particular, A and C had the lowest values (Table 1). For both growing media, results were proportional to the amount of perlite (25%), the inorganic component. For F and G (control) which included 12.5% and the 25% of perlite and lapillus, respectively, the OM decreased. Meanwhile, B, D, and E incorporated biochar without any inorganic materials, and these showed higher levels of OM. It is noteworthy that OM content was relatively constant when biochar was 25% and 50%. Biochar appears to supply OM quantities similar to black peat and compost. High OM can improve water availability and water capacity and reduce compaction. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Growing** & **Total Nitrogen** & **Organic Matter** & & & **Electrical Conductivity** \\
**Mediuma** & **(N) (g kg\({}^{-1}\))** & **(\%)** & & & & **(dS/m\({}^{-1}\) 25\({}^{\circ}\) C)** \\ \hline  & **Start** & **Start** & **Start** & **End** & **Start** & **End** \\ \hline A & 1.96 \(\pm\) 0.07 b & 7.03 \(\pm\) 0.03 c & 5.08 \(\pm\) 0.22 b & 5.20 \(\pm\) 0.22 b & 1.64 \(\pm\) 0.02 C & 0.99 \(\pm\) 0.04 A \\ B & 2.24 \(\pm\) 0.05 ab & 16.96 \(\pm\) 0.07 a & 7.00 \(\pm\) 0.18 a & 5.30 \(\pm\) 0.78 b & 1.52 \(\pm\) 0.06 C & 0.41 \(\pm\) 0.03 B \\ C & 1.68 \(\pm\) 0.02 b & 8.69 \(\pm\) 0.12 c & 6.00 \(\pm\) 0.16 ab & 4.95 \(\pm\) 0.20 b & 1.75 \(\pm\) 0.04 C & 0.47 \(\pm\) 0.10 B \\ D & 2.80 \(\pm\) 0.04 a & 15.72 \(\pm\) 0.18 a & 6.05 \(\pm\) 0.14 ab & 5.02 \(\pm\) 0.25 b & 1.67 \(\pm\) 0.06 C & 0.69 \(\pm\) 0.07 B \\ E & 2.94 \(\pm\) 0.06 a & 16.34 \(\pm\) 0.27 a & 7.36 \(\pm\) 0.11 a & 7.37 \(\pm\) 0.33 a & 3.15 \(\pm\) 0.20 B & 0.85 \(\pm\) 0.04 B \\ F & 3.08 \(\pm\) 0.81 a & 11.07 \(\pm\) 0.08 b & 7.56 \(\pm\) 0.19 a & 7.18 \(\pm\) 0.14 a & 4.37 \(\pm\) 0.06 A & 0.85 \(\pm\) 0.05 B \\ G & 2.24 \(\pm\) 0.03 ab & 10.34 \(\pm\) 0.03 b & 4.66 \(\pm\) 0.17 b & 5.37 \(\pm\) 0.11 b & 4.37 \(\pm\) 0.08 A & 0.75 \(\pm\) 0.06 B \\ \hline \end{tabular}  
* Growing media was 50% sandy soil + 50% of the following: A = black peat and perlite 1:1; B = biochar 1; C = black peat, perlite, and biochar 0.5:1:0.5; D = black peat and biochar 1:1; E = black peat, compost, and biochar 0.5:0.5:1; F = black peat, perlite, compost, and biochar 0.5:0.5:0.5; G = black peat and lapillus 1:1 (control, mixture adopted by the hosting nursery).  
\end{table} 
Table 1: Growing media chemical properties observed at the start (November 2013) and end (October 2015) of the trial. Values are means (\(\pm\)standard deviation). The b letter in a column indicate significant differences (lowercase indicate \(p<0.05\), uppercase indicate \(p<0.001\)) compared to the letter a and c based on [PERSON]’s honest significant difference (HSD) test.