Control | N addition | Precipitation reduction | Combined effects | ||
---|---|---|---|---|---|
15N (‰) | Foliage | −0.98 ± 0.03 | − 0.43 ± 0.05 | − 0.80 ± 0.01 | 0.73 ± 0.03 |
Litterfall | −1.82 ± 0.07 | −0.56 ± 0.02 | −1.45 ± 0.04 | − 0.10 ± 0.02 | |
Fine roots (< 2 mm) | − 0.46 ± 0.04 | − 1.43 ± 0.04 | − 0.32 ± 0.10 | 0.09 ± 0.05 | |
Coarse roots (> 2 mm) | − 0.76 ± 0.03 | −1.72 ± 0.02 | −1.09 ± 0.10 | − 0.19 ± 0.09 | |
Soil layer (0–10 cm) | − 0.11 ± 0.02 | 1.79 ± 0.13 | 0.86 ± 0.01 | 1.23 ± 0.20 | |
Soil layer (10–20 cm) | 3.37 ± 0.10 | 2.32 ± 0.16 | 3.35 ± 0.11 | 3.62 ± 0.22 | |
Soil layer (20–30 cm) | 6.64 ± 0.09 | 6.14 ± 0.40 | 6.44 ± 0.11 | 6.46 ± 0.08 | |
N (%) | Foliage | 2.55 ± 0.01 | 2.45 ± 0.07 | 2.32 ± 0.02 | 2.35 ± 0.07 |
Litterfall | 1.11 ± 0.01 | 1.38 ± 0.03 | 1.01 ± 0.04 | 1.06 ± 0.02 | |
Fine roots (< 2 mm) | 1.50 ± 0.01 | 1.35 ± 0.00 | 1.47 ± 0.01 | 1.46 ± 0.07 | |
Coarse roots (> 2 mm) | 0.77 ± 0.00 | 0.61 ± 0.03 | 0.85 ± 0.08 | 0.79 ± 0.06 | |
Soil layer (0–10 cm) | 1.71 ± 0.06 | 1.37 ± 0.01 | 1.71 ± 0.08 | 1.71 ± 0.02 | |
Soil layer (10–20 cm) | 1.03 ± 0.07 | 1.19 ± 0.02 | 1.01 ± 0.05 | 1.18 ± 0.10 | |
Soil layer (20–30 cm) | 0.18 ± 0.01 | 0.16 ± 0.01 | 0.29 ± 0.01 | 0.25 ± 0.08 |