TABLE 1.
Soil physicochemical variables following application of long-term inorganic and organic fertilizersa
| Treatment | Mean value ± SEM |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| pH (1:5 soil/H2O ratio) | SOC concn (g C kg−1) | DOC concn (mg C kg−1) | TN concn (g N kg−1) | NH4+ concn (mg N kg−1) | NO3− concn (mg N kg−1) | DON concn (mg N kg−1) | AP concn (mg P kg−1) | AK concn (mg K kg−1) | DCo (10−6 m2 s−1) | |
| Control | 4.96 ± 0.02a | 5.69 ± 0.10a | 4.27 ± 0.37a | 0.59 ± 0.01a | 0.54 ± 0.17ab | 12.50 ± 0.39c | 9.22 ± 0.37c | 5.25 ± 0.54a | 84.7 ± 10.38a | 12.58 ± 0.39a |
| N | 5.20 ± 0.01b | 6.44 ± 0.26b | 4.38 ± 0.23a | 0.70 ± 0.01b | 0.66 ± 0.04b | 8.60 ± 0.77ab | 5.56 ± 0.24ab | 15.0 ± 3.12bc | 177.6 ± 23.00b | 10.71 ± 0.60b |
| NL | 6.59 ± 0.04d | 6.32 ± 0.08b | 5.33 ± 0.34a | 0.72 ± 0.02b | 0.56 ± 0.19ab | 5.21 ± 0.81a | 4.28 ± 0.75a | 16.4 ± 1.82c | 203.1 ± 5.62c | 9.95 ± 0.19b |
| NPS | 5.13 ± 0.03b | 6.62 ± 0.06bc | 4.35 ± 0.20a | 0.78 ± 0.02c | 0.69 ± 0.10b | 8.71 ± 0.60ab | 5.38 ± 0.57ab | 10.3 ± 0.95b | 178.0 ± 2.42b | 9.96 ± 0.85b |
| NRS | 5.16 ± 0.02b | 7.13 ± 0.28c | 5.53 ± 0.60a | 0.82 ± 0.02cd | 0.41 ± 0.13ab | 8.66 ± 0.08ab | 8.90 ± 2.88bc | 10.8 ± 0.52b | 206.7 ± 4.16c | 8.20 ± 0.55c |
| NR | 5.17 ± 0.02b | 6.76 ± 0.29bc | 5.63 ± 0.85a | 0.82 ± 0.01cd | 0.25 ± 0.07a | 11.6 ± 2.24bc | 5.93 ± 0.46abc | 11.6 ± 0.72bc | 204.8 ± 0.99c | 9.70 ± 0.66bc |
| NPM | 5.58 ± 0.02c | 8.21 ± 0.20d | 12.3 ± 1.80b | 0.85 ± 0.02d | 0.49 ± 0.03ab | 9.56 ± 0.50bc | 5.89 ± 0.45abc | 157 ± 8.85d | 170.8 ± 3.86b | 2.81 ± 0.35d |
a
n = 3. Values within the same row followed by different letters indicate significant differences at a P value of <0.05. SOC, soil organic carbon; DOC, dissolved organic carbon; TN, soil total nitrogen; DON, dissolved organic nitrogen; AP, available phosphorus; AK, available potassium; DCo, effective diffusion coefficient of oxygen.