TABLE 1.
Variation in inhibition and resistance, Shannon diversity, and density of culturable bacteria and streptomycetes among locations and depthsa
| Location or depth | N | Mean inhibition zone size (mm) | Mean resistance zone size (mm) | Diversity (H) | Density of culturable bacteria (CFU/g) | Density of streptomycetes (CFU/g) |
|---|---|---|---|---|---|---|
| Location 1 | 49 | 1.73a | 3.87ab | 3.41 ± 0.02 | 1.7 × 106a | 1.5 × 105b |
| Location 2 | 55 | 1.30b | 3.22b | 3.38 ± 0.02 | 1.4 × 106a | 2.6 × 105a |
| Location 3 | 49 | 0.94b | 4.32a | 2.94 ± 0.03 | 1.2 × 106a | 1.1 × 105b |
| Depth 1 | 44 | 1.60a | 3.14b | 2.66 ± 0.03 | 1.7 × 106a | 1.9 × 105a |
| Depth 2 | 41 | 1.02a | 4.04ab | 3.17 ± 0.03 | 1.3 × 106a | 2.1 × 105a |
| Depth 3 | 34 | 1.44a | 4.22a | 3.44 ± 0.02 | 1.5 × 106a | 1.5 × 105a |
| Depth 4 | 34 | 1.21a | 3.87ab | 2.97 ± 0.03 | 1.2 × 106a | 1.4 × 105a |
a
Depths 1 to 4 correspond to soil depths of 0 to 2, 2 to 4, 4 to 6, and 6 to 8 cm, respectively. N is the sample size of CCNHA streptomycete isolates. Raw mean zone sizes, measured in millimeters, are reported. For resistance, a smaller mean zone size indicates greater resistance. Values followed by the same letter(s) are not significantly different at P < 0.05 (least significant difference). Standard deviations for Shannon diversity (H) are presented.