Table 3. F-values and p-values (in parentheses) for significance tests of the effects of nitrogen (N) and litter treatments on soil extracellular enzyme activities and microbial variables in a mixed pine/oak forest in central North China.
| Variable | Factor | Time of sampling |
repeated measurements | ||
|---|---|---|---|---|---|
| Jun. 2014 | Aug. 2014 | Oct. 2014 | |||
| BG | N | 0.024 (0.977) | 0.092 (0.912) | 2.439 (0.096) | 0.398 (0.674) |
| Litter | 3.335 (0.026)* | 8.841 (0.000)*** | 1.467 (0.233) | 4.208 (0.010)* | |
| N × Litter | 0.609 (0.722) | 0.775 (0.593) | 0.305 (0.931) | 0.408 (0.870) | |
| NAG | N | 0.214 (0.808) | 0.430 (0.652) | 6.217 (0.045)* | 1.440 (0.247) |
| Litter | 22.24 (0.000)*** | 28.07 (0.000)*** | 5.424 (0.002)** | 15.90 (0.000)*** | |
| N × Litter | 0.972 (0.455) | 0.244 (0.960) | 2.306 (0.049)* | 1.075 (0.391) | |
| PO | N | 0.714 (0.494) | 0.011 (0.989) | 0.203 (0.817) | 0.225 (0.800) |
| Litter | 15.21 (0.002)** | 8.688 (0.000)*** | 8.712 (0.033)* | 5.727 (0.002)** | |
| N × Litter | 0.708 (0.645) | 0.720 (0.636) | 0.137 (0.991) | 0.261 (0.952) | |
| PER | N | 1.895 (0.160) | 0.920 (0.404) | 0.587 (0.559) | 0.251 (0.779) |
| Litter | 3.108 (0.375) | 3.254 (0.028)* | 6.156 (0.104) | 3.270 (0.030)* | |
| N × Litter | 0.199 (0.976) | 0.419 (0.863) | 0.270 (0.948) | 0.189 (0.978) | |
| MBC | N | 0.086 (0.918) | 0.084 (0.919) | 2.422 (0.098) | 0.569 (0.570) |
| Litter | 2.561 (0.064) | 2.764 (0.050)* | 0.507 (0.679) | 6.349 (0.001)** | |
| N × Litter | 0.662 (0.681) | 0.369 (0.895) | 0.535 (0.779) | 0.793 (0.580) | |
| MBN | N | 0.232 (0.793) | 0.144 (0.866) | 2.878 (0.064) | 0.752 (0.477) |
| Litter | 3.131 (0.033)* | 3.946 (0.013)* | 0.587 (0.626) | 3.506 (0.022)* | |
| N × Litter | 1.001 (0.436) | 0.333 (0.916) | 0.303 (0.933) | 0.464 (0.832) | |
| MR | N | 0.115 (0.891) | 0.615 (0.554) | 0.073 (0.929) | 0.044 (0.957) |
| Litter | 6.097 (0.001)** | 9.435 (0.000)*** | 8.182 (0.000)*** | 9.155 (0.000)*** | |
| N × Litter | 0.546 (0.771) | 0.555 (0.764) | 0.908 (0.498) | 0.542 (0.774) | |
Treatments began in September 2009 and were applied annually. BG, β-glucosidase; NAG, N-acetyl-β-glucosaminidase; PO, phenol oxidase; PER, peroxidase; MBC, microbial biomass carbon; MBN, microbial biomass nitrogen; MR, microbial activity. *p < 0.05; **p < 0.01; ***p < 0.001; values in italic are results based on non-parametric tests.