Table 5. Regressions of organic material quality variables and soil properties with microbial parameters (n = 54) at the end of the 1st and 12th months with the amendment of different organic materials (P < 0.05).
| Regression equation | R2 |
|---|---|
| 1 month | |
| MBC = 467.895–1.526 C/N—1.347 clay | 0.38 |
| MBN = 13.087 + 67.799 OTN | 0.44 |
| AWCD = 0.267 + 0.010 clay | 0.24 |
| Shannon index (H’) = 5.038–2.801 STN + 0.127 SOC– 0.200 lignin | 0.78 |
| Simpson index (D) = 1.057–0.018 pH– 0.021 lignin | 0.48 |
| McIntosh index (U) = 3.300 + 0.078 clay—5.653 OTN | 0.36 |
| 12 month | |
| MBC = 154.602 + 3.788 C/N | 0.43 |
| MBN = 21.122 + 0.870 C/N | 0.22 |
| AWCD = 1.105–0.081 SOC+ 0.010 C/N | 0.84 |
| Shannon index (H’) = 2.921–0.077 SOC + 0.014 C/N + 0.006 clay | 0.73 |
| Simpson index (D) = 0.938–0.007 SOC + 0.001 C/N + 0.001 clay | 0.68 |
| McIntosh index (U) = 7.769–0.524 SOC + 0.073 C/N | 0.86 |
Soil properties: SOC, soil organic carbon; STN, soil total nitrogen; clay; pH; Organic material quality: OTN, total nitrogen; C/N ratio; lignin.