| Table 1. Physico-chemical characteristics of organic and clay substrates collected on a spruce-feather moss site located in the Clay Belt of Quebec (Canada) for use in the greenhouse, transplanting experiment. | ||||||||
| Substrates | Degree of decomposition | pH | CEC (meq 100g–1) | N (g kg–1) | P (g kg–1) | K (g kg–1) | Mg (g kg–1) | Ca (g kg–1) |
| Clay a | - | 5.7 | 25.9 | 0.9 | 0.005 | 0.08 | 0.28 | 1.57 |
| Fibric b | Low | 3.2–4 | 124 | 5–10 | 0.1 | 0.08 | 1 | 0.9 |
| Mesic b | Moderate | 4–7 | 116 | 8–11 | 3.5 | 5.7 | 4.4 | 2.4 |
| Humic b | High | 3.5–8 | 160 | 9–19 | 8 | 12.5 | 4.9 | 6 |
| a: sampled clay (60 samples) on the prepared site (Clay-Belt). b: (Henneb et al. 2019; Soil Classification Working Group 1998). | ||||||||
Fig. 1. Randomized distribution of 130 potted black spruce seedlings on the greenhouse bench. The pots contained black spruce seedlings transplanted into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada).
| Table 2. Mean temperatures (°C) of the greenhouse and substrates over the 6-month duration of an experiment looking at black spruce seedling growth and nutrition after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). Means followed by the same letter are not statistically different (P ≥ 0.05). | ||
| Mean temperature (°C) | ||
| Greenhouse | 22.6 (0.151) b | |
| Substrates | Fibric | 20.1 (0.151) ab |
| Mesic | 19.7 (0.151) a | |
| Humic | 19.6 (0.151) a | |
| Clay | 20.0 (0.151) a | |
| Organic-mix | 20.0 (0.062) a | |
| Organic-Clay | 20.0 (0.087) a | |
| The values in parentheses represent the standard deviation. | ||
| Table 3. Black spruce seedling mortality as a function of substrate type, over the 6-month duration of an experiment looking at seedling responses after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). | ||
| Substrates groups | Mortality (number of seedlings) | Mortality rate (%) |
| 1) Fibric | 0 | 0 |
| 2) Mesic | 1 | 10 |
| 3) Humic | 4 | 40 |
| 4) Clay | 3 | 30 |
| 5) Organic-mix | 8 | 13.3 |
| 6) Organic-Clay mix | 1 | 3.3 |
| Table 4. ANOVA summary of substrate effects (degrees of freedom = 5) on black spruce seedling growth, biomass, and foliar nutrient concentrations at the end of the 6-month duration of an experiment looking at seedling responses after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). | ||
| Response variable | F-Value | P-Value |
| Seedling height increase (%) | 2.266 | 0.014 |
| Seedling diameter increase (%) | 1.894 | 0.044 |
| Total biomass increase (%) | 0.695 | 0.630 |
| Root biomass (g) | 1.189 | 0.330 |
| Foliar total N (g kg–1) | 4.525 | < 0.001 |
| Foliar P (g kg–1) | 2.659 | 0.001 |
| Foliar K (g kg–1) | 2.227 | 0.021 |
| Foliar Mg (g kg–1) | 1.145 | 0.339 |
| Foliar Ca (g kg–1) | 1.075 | 0.401 |
| Values in bold type indicate significance at P = 0.05. | ||
| Table 5. Summary of multiple means comparisons concerning substrate effects on black spruce seedling growth and foliar nutrient concentrations at the end of the 6-month duration of an experiment looking at seedling responses after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). For each variable (column), means followed by the same letter do not differ at P = 0.05. | |||||||
| Substrates | Height increase (%) | Diameter increase (%) | N (g kg–1) | P (g kg–1) | K (g kg–1) | Ca (g kg–1) | Mg (g kg–1) |
| Fibric | 41.8 ab | 88.7 ab | 8.4 ab | 1.4 ab | 4.3 ab | 14.1 a | 1.9 a |
| Mesic | 40.8 ab | 119.9 b | 11.4 c | 1.8 b | 4.6 ab | 18.7 a | 2.1 a |
| Humic | 31.8 a | 85.2 a | 9.9 bc | 1.7 b | 4.6 ab | 17 a | 1.9 a |
| Clay | 50.8 b | 92.6 ab | 6.3 a | 1.2 a | 4.0 a | 15 a | 2.0 a |
| Organic-mix | 39.6 a | 108.4 ab | 9.2 b | 1.8 b | 5.1 b | 15.8 a | 2.0 a |
| Organic-Clay mix | 39.9 ab | 94.4 ab | 6.9 a | 1.7 b | 5.2 b | 16.4 a | 2.0 a |
Fig. 2. Principal component analysis (PCA) summarizing associations that exist between the substrates, black spruce seedling growth and nutrition at the end of the 6-month duration of an experiment looking at seedling responses after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). PCA explains 53.8% of the variation.
Fig. 3. Contribution (%) of the variables to the axes 1 and 2 of the principal component analysis that summarized the relationships between the substrates, growth and nutrition of black spruce seedling at the end of the 6-month duration of an experiment looking at seedling responses after transplantation into six substrates prepared from field-harvested material collected in a spruce-feather moss site located on the Clay Belt of Quebec and Ontario (Canada). The red dotted line indicates the expected average contribution for each axis. A variable whose contribution is greater than this limit can be considered important in its contribution to the variance on each axis.