Table 2.
General soil properties before the experiment started in 2001 (0–20 cm soil depth).
| Treatment | pH | SOM | TN | TP | aAvailable K | Bulk density |
|---|---|---|---|---|---|---|
| (g/kg) | (g/kg) | (g/kg) | (g/kg) | (g/cm3) | ||
| CK | 6.51 | 26.90 | 2.53 | 0.62 | 0.22 | 1.17 |
| RP | 6.69 | 24.50 | 2.49 | 0.65 | 0.24 | 1.21 |
| RR | 6.82 | 25.60 | 2.50 | 0.63 | 0.23 | 1.12 |
| RC | 6.62 | 29.10 | 2.46 | 0.66 | 0.23 | 1.24 |
| ROM | 6.43 | 27.50 | 2.69 | 0.61 | 0.22 | 1.11 |
| ROF | — | — | — | — | — | — |
| Means | 6.61 | 26.72 | 2.53 | 0.64 | 0.23 | 1.17 |
| bCV% | 2.30 | 4.81 | 3.32 | 3.08 | 3.61 | 4.85 |
aAvailable K was extracted with 1 mol NH4AC.
bC.V. is coefficient of variation.
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.