Table 2 Pearson correlation coefficients (r) between live or dead fine root mass and selected abiotic and biotic factors, across all genotypes and for each genotype, in 14 year-old hybrid poplar plantations.
Factors correlated to live fine root biomass (kg/ha) | r | P-value | Factors correlated to dead fine root biomass (kg/ha) | r | P-value |
|---|---|---|---|---|---|
Across all genotypes (n = 27) | Across all genotypes (n = 27) | ||||
Leaf litter P (%) | −0.70 | <0.0001 | Soil NH4 supply (µg/10 cm2/42d) | 0.72 | <0.0001 |
Leaf litter N (%) | −0.68 | 0.0001 | Leaf litter mass remaining after 1 yr (%) | 0.67 | 0.0001 |
Soil NO3 supply (µg/10 cm2/42d) | −0.53 | 0.005 | Site elevation (m) | 0.62 | 0.0006 |
Soil base saturation (%) | −0.51 | 0.006 | Live fine root biomass (kg/ha) | 0.61 | 0.0008 |
Soil pH | −0.48 | 0.01 | Soil pH | −0.58 | 0.001 |
Leaf litter mass remaining after 1 yr (%) | 0.47 | 0.01 | Soil CEC (meq/100 g) | −0.49 | 0.009 |
Site elevation (m) | 0.47 | 0.01 | Leaf litter N (%) | −0.49 | 0.010 |
Soil sand content (%) | 0.47 | 0.01 | Soil NO3 supply (µg/10 cm2/42d) | −0.46 | 0.02 |
Soil bulk density (g/cm3) | −0.46 | 0.01 | Leaf litter C (%) | 0.44 | 0.02 |
Soil CEC (meq/100 g) | −0.45 | 0.02 | Leaf litter P (%) | −0.42 | 0.03 |
Soil C:N ratio | 0.44 | 0.02 | Soil clay content (%) | −0.42 | 0.03 |
Soil clay content (%) | −0.42 | 0.03 | Soil stoniness (%) | 0.42 | 0.03 |
Soil Ca supply (µg/10 cm2/42d) | −0.38 | 0.05 | Genotype DN × M (n = 9) | ||
Soil stoniness (%) | 0.38 | 0.05 | Soil NH4 supply (µg/10 cm2/42d) | 0.80 | 0.009 |
Genotype DN × M (n = 9) | Leaf litter mass remaining after 1 yr (%) | 0.75 | 0.02 | ||
Soil silt content (%) | −0.77 | 0.02 | Leaf litter Ca (%) | −0.75 | 0.02 |
Soil sand content (%) | 0.70 | 0.04 | Soil Ca supply (µg/10 cm2/42d) | −0.66 | 0.05 |
Soil C:N ratio | 0.68 | 0.05 | Aboveground biomass (kg/tree) | −0.66 | 0.05 |
Soil NO3 supply (µg/10 cm2/42d) | −0.67 | 0.05 | Genotype D × N (n = 9) | ||
Aboveground biomass (kg/tree) | −0.67 | 0.05 | Soil NH4 supply (µg/10 cm2/42d) | 0.79 | 0.01 |
Genotype D × N (n = 9) | Soil K (µg/10 cm2/42d) | −0.79 | 0.01 | ||
Leaf litter mass remaining after 1 yr (%) | 0.76 | 0.02 | Leaf litter mass remaining after 1 yr (%) | 0.79 | 0.01 |
Site elevation (m) | 0.70 | 0.04 | Site elevation (m) | 0.75 | 0.02 |
Genotype M × B (n = 9) | Soil CEC (meq/100 g) | −0.66 | 0.05 | ||
Leaf litter P (%) | −0.85 | 0.003 | Genotype M × B (n = 9) | ||
Leaf litter N (%) | −0.82 | 0.007 | Live fine root biomass (kg/ha) | 0.86 | 0.003 |
Soil sand content (%) | 0.82 | 0.007 | Soil C:N Ratio | 0.78 | 0.01 |
Soil base saturation (%) | −0.76 | 0.02 | Leaf litter N (%) | −0.76 | 0.02 |
Soil C:N ratio | 0.73 | 0.03 | Leaf litter P (%) | −0.69 | 0.04 |
Soil CEC (meq/100 g) | −0.71 | 0.03 | Soil sand content (%) | 0.67 | 0.05 |
Soil P supply (µg/10 cm2/42d | −0.70 | 0.04 | Soil base saturation (%) | −0.67 | 0.05 |
Soil NO3 supply (µg/10 cm2/42d) | −0.69 | 0.04 | |||
Soil pH | −0.66 | 0.05 | |||
Site elevation (m) | 0.66 | 0.05 | |||
Soil clay content (%) | −0.66 | 0.05 | |||
