Table 1 Changes in selected soil chemical properties after 9 years of N addition in the larch plantation
Soil depth/treatments | Organic C (g kg−1) | Total N (g kg−1) | Soil C:N | NH4 +-N (mg kg−1) | NO3 −-N (mg kg−1) | Extractable Al (%) | Extractable Fe (%) | pH |
|---|---|---|---|---|---|---|---|---|
0–10-cm depth | ||||||||
Control | 80.8 a | 7.2 a | 11.2 b | 3.5 a | 23.9 b | 0.231 b | 0.309 b | 5.8 a |
N addition | 85.4 a | 7.3 a | 11.7 a | 3.0 a | 91.7 a | 0.254 a | 0.316 b | 5.3 b |
10–20-cm depth | ||||||||
Control | 48.1 b | 5.0 b | 9.6 c | 2.6 a | 12.3 c | 0.255 a | 0.358 a | 6.0 a |
N addition | 46.6 b | 4.6 b | 10.0 c | 2.4 a | 48.6 b | 0.278 a | 0.353 a | 5.8 a |