Table 5.
Soil organic carbon content, dissolved organic content, and soil microbial organic content in 0–10 and 10–20 cm depth
| Rotation | SOM | DOC | MBC | SOM | DOC | MBC |
|---|---|---|---|---|---|---|
| (g/kg) | (g/kg) | (g/kg) | (g/kg) | (mg/kg) | (g/kg) | |
| 0–10 cm | 10–20 cm | |||||
|
| ||||||
| CK | 21.6b | 0.08b | 0.76b | 22.2ab | 0.07b | 0.64b |
| RC | 25.8a | 0.16a | 1.08a | 21.4b | 0.13a | 1.11a |
| ROF | 20.3bc | 0.15a | 1.22a | 16.6c | 0.12a | 1.08a |
| ROM | 18.9c | 0.09b | 0.51b | 17.1c | 0.15a | 0.44b |
| RP | 23.7a | 0.20a | 0.57b | 23.4a | 0.08b | 0.60b |
| RR | 21.3b | 0.19a | 1.09a | 18.6c | 0.14a | 1.04a |
|
| ||||||
| Comparison of depth | ||||||
| 0–10 cm | 21.93a | 0.15 | 0.87 | |||
| 10–20 cm | 19.88b | 0.11 | 0.82 | |||
|
| ||||||
| ANOVA | ||||||
| Rotation | ∗∗ | ∗∗ | ∗∗ | |||
| Depth | ∗∗ | ns | ns | |||
| R × D | ∗∗ | ∗∗ | ∗∗ | |||
Means on the same column and for the same sampling time followed by the same letter (or none) are not significantly different at P < 0.05 by Tukey Test; ns: not significant; *P < 0.05; **P < 0.01. Abbreviations: CK: rice-fallow phase; RR: rice-ryegrass; RP: rice-potato, with rice straw as mulch; RC: rice-Chinese milk vetch; ROM: rice-oilseed rape with burned straw return after harvest; ROF: rice-oilseed rape with fresh straw return as mulch at flowering.