Mean (n = 30) and standard error of the mean (SE) for total soil organic matter (SOM), particulate organic matter (POM), potassium permanganate oxidizable carbon (POXC), potentially mineralizable carbon (PMC), Solvita® (Solvita, Woodsend Laboratories, Augusta, ME, USA) soil respiration (SOLV), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN).
| Property | Nulla | Lowa | Higha | P-value | |||
|---|---|---|---|---|---|---|---|
| Mean | SE | Mean | SE | Mean | SE | ||
| SOM (%) | 6.9 | 0.6 | 7.2 | 0.6 | 7.4 | 0.7 | 0.9012 |
| POM (%) | 1.4 | 0.1 | 1.6 | 0.1 | 1.5 | 0.1 | 0.6372 |
| POXC (mg/kg) | 1,020 | 54.9 | 850 | 57.5 | 991 | 53.5 | 0.0793 |
| PMC (mg/kg/d) | 77.4 | 7.6 | 91.6 | 5.5 | 86.3 | 7.3 | 0.3492 |
| SOLV (mg/kg/d) | 32.4b | 0.5 | 33.8ab | 0.4 | 33.9a | 0.4 | 0.0275* |
| MBC (mg/kg) | 39.5 | 3.7 | 45.9 | 5.8 | 48.3 | 4.4 | 0.4167 |
| MBN (mg/kg) | 8.6 | 0.7 | 9.9 | 1.4 | 8.9 | 0.8 | 0.6717 |
↵aData is from the fall sampling period. Treatments are high, low, and no biosolids application (null). The P-values for the analysis of variance (ANOVA) are given. Letters identify Tukey-Kramer Honestly Significant Difference (HSD) mean separations with unique letters identifying significant differences.
↵*P ≤ 0.05