Table 1. The soil organic carbon (SOC), total nitrogen (N), soil microbial biomass carbon (SMB-C), soil microbial biomass nitrogen (SMB-N), potential C (Cmin) and N (Nmin) mineralization, SMB-C/SMB-N, SMB-C/SOC, and CO2/SMB-C (qCO2) in bulk soil from the control (CK) or soil that has received 32 years of chemical fertilizer application (N, P: phosphorus, K: potassium) and either 0 (M0), 30 (M30) or 60 (M60) t manure ha-1 yr-1.
| Treatment | SOC | Total N | SMBC | SMBN | Cmin | Nmin | SMBC:SMBN | SMBC:SOC | qCO2 |
|---|---|---|---|---|---|---|---|---|---|
| g kg-1 | mg kg-1 | % | |||||||
| CK | |||||||||
| M0 | 16.9e | 1.76d | 285e | 52.1c | 151.0a | 10.8de | 5.5ef | 1.7cd | 0.54a |
| M30 | 23.8d | 2.29c | 611bcd | 99.7a | 136.1ab | 17.3cd | 6.1def | 2.6a | 0.22b |
| M60 | 27.5b | 2.75b | 641bc | 72.3bc | 123.3ab | 32.4a | 8.9bc | 2.3ab | 0.19b |
| N | |||||||||
| M0 | 16.6e | 1.79d | 349e | 55.5bc | 155.5a | 10.9de | 6.3def | 2.1abcd | 0.45a |
| M30 | 25.5c | 2.54bc | 512d | 63.7bc | 99.2b | 14.4cd | 8.0cd | 2.0bcd | 0.19b |
| M60 | 30.8a | 3.16a | 687ab | 61.8bc | 125.6ab | 20.2bc | 11.1ab | 2.2abc | 0.18b |
| NPK | |||||||||
| M0 | 17.0e | 1.80d | 267 e | 53.0c | 122.5ab | 16.7cd | 5.0f | 1.6d | 0.46a |
| M30 | 22.7d | 2.43bc | 544cd | 77.2ab | 139.6ab | 7.0e | 7.0de | 2.4ab | 0.25b |
| M60 | 30.6a | 3.45a | 791a | 68.6bc | 138.6ab | 26.1ab | 11.5a | 2.6a | 0.18b |
Note: Different letters indicate significant differences at 5% probability level under different treatments.