Table 3.
Soil characteristics for bulk soil (3–20 cm depth) collected at arable fields of 10 organic farms in 2004, 2005, and 2006 at different locations within the Netherlands, ordered from low to high Lysobacter spp. populations (gene numbers expressed as log g−1 soil)
| Year | Farm codea | Crop | Soil typeb | Clay particles (<2 μm) (%)b | pH-KClb | Organic matter (%)b | C/N quotientb | Lysobacter gene copies (log g−1 soil)d | Total bacteria gene copies (log g−1 soil) | Lysobacter percentage of total bacteria |
|---|---|---|---|---|---|---|---|---|---|---|
| 2004 | C | Grass–clover | Sandy soil | 2.0 | 5.2 | 10.2 | 26.1 | <4.00 (4/3) | 8.27 | – |
| 2005 | C | Wheat | Sandy soil | 1.5 | 5.1 | 10.8 | 18.4 | 4.71 (2/1) | 8.87 | 0.01 |
| 2005 | F | Grass–clover | Sandy soil | 2.0 | 4.9 | 3.8 | 16.7 | 5.57 | 9.12 | 0.03 |
| 2004 | F | Triticale, grass–clover | Sandy soil | 2.0 | 4.7 | 2.8 | 18.9 | 5.69 (2/0) | 9.11 | 0.04 |
| 2006 | J | Pumpkin | Sandy soil | 2.5 | 4.9 | 1.7 | 23.2 | 5.71 | 8.40 | 0.21 |
| 2006 | F | Wheat, winter radish | Sandy soil | 1.5 | 5.0 | 2.6 | 19.0 | 5.75 (1/0) | 8.43 | 0.21 |
| 2004 | J | Pumpkin | Sandy soil | 1.8 | 5.4 | 1.9 | 21.3 | 5.76 (3/1) | 8.84 | 0.08 |
| 2005 | J | Alfalfa | Sandy soil | 1.8 | 5.4 | 2.4 | 18.1 | 5.87 (2/1) | 8.05 | 0.67 |
| 2006 | A | Red beet | Marine clay | 12.3 | 7.4 | 1.9 | 12.7 | 6.22 | 9.11 | 0.13 |
| 2005 | A | Carrot | Marine clay | 12.0 | 7.5 | 2.3 | 9.2 | 6.25 | 8.21 | 1.09 |
| 2006 | Aa | Grass-clover | Marine clay | 24.3 | 7.4 | 2.7 | 10.1 | 6.27 | 8.86 | 0.26 |
| 2006 | I | Pea | Marine clay | 28.0 | 7.4 | 2.5 | 11.9 | 6.37 | 8.94 | 0.27 |
| 2005 | I | Sugar beet | Marine clay | 27.3 | 7.6 | 2.7 | 10.1 | 6.37 | 8.61 | 0.58 |
| 2006 | D | Potato | Marine clay | 13.8 | 7.4 | 3.0 | 13.3 | 6.44 | 9.30 | 0.14 |
| 2005 | B | Carrot | Marine clay | 13.5 | 7.3 | 2.5 | 9.7 | 6.44 (1/0) | 8.54 | 0.80 |
| 2006 | Ga | Grass-clover | Marine clay | 15.5 | 7.4 | 4.0 | 12.7 | 6.47 | 9.34 | 0.13 |
| 2006 | Ea | Grass-clover | Marine clay | 23.5 | 7.2 | 8.9 | 11.9 | 6.48 | 9.18 | 0.20 |
| 2005 | G | Wheat | Marine clay | 14.0 | 5.9 | 12.0 | 11.7 | 6.51 (1/0) | 8.30 | 1.60 |
| 2006 | E | Cabbage | Marine clay | 26.3 | 7.2 | 7.5 | 11.1 | 6.51 | 9.01 | 0.32 |
| 2006 | Da | Grass-clover | Marine clay | 14.3 | 7.6 | 2.9 | 13.6 | 6.51 | 9.13 | 0.24 |
| 2005 | D | Broccoli | Marine clay | 13.3 | 7.5 | 3.5 | 12.6 | 6.54 | 8.56 | 0.95 |
| 2005 | H | Celery | Marine clay | 20.3 | 7.5 | 3.5 | 9.8 | 6.57 (1/0) | 8.88 | 0.49 |
| 2004 | A | Wheat | Marine clay | 11.5 | 7.4 | 1.7 | 13.6 | 6.57 (1/0) | 8.72 | 0.70 |
| 2004 | B | Cauliflower | Marine clay | 13.8 | 7.3 | 1.6 | 12.4 | 6.58 (1/0) | 8.72 | 0.71 |
| 2005 | E | Wheat | Marine clay | 25.8 | 7.2 | 4.1 | 10.6 | 6.63 | 8.53 | 1.25 |
| 2004 | I | Grass-clover | Marine clay | 29.3 | 7.4 | 1.9 | 15.7 | 6.64 (1/0) | 8.33 | 2.03 |
| 2006 | G | Parsnip, pumpkin | Marine clay | 16.3 | 7.0 | 9.4 | 12.7 | 6.65 | 9.59 | 0.11 |
| 2004 | E | Shallot, winter radish | Marine clay | 27.5 | 7.2 | 6.8 | 11.6 | 6.67 | 8.83 | 0.69 |
| 2004 | D | Onion | Marine clay | 11.8 | 7.5 | 2.9 | 18.4 | 6.79 | 8.69 | 1.26 |
| 2004 | G | Brussels sprouts | Marine clay | 19.0 | 6.8 | 10.3 | 13.4 | 6.95 (1/0) | 9.54 | 0.26 |
| 2004 | H | Cabbage | Marine clay | 20.5 | 7.4 | 2.9 | 12.2 | 6.95 (1/0) | 8.67 | 1.90 |
| LSDc | 2.4 | 0.4 | 1.5 | 2.3 | 0.51 | ns |
a“a” is a field from the same farm but with grass–clover
bData are compiled from previous research [24]
cLeast significant differences (LSD) at P = 0.05; four replicates per treatment; ns no significant differences
dBetween brackets: number of undetectable samples/number of samples with inhibition; 104 is estimated to be the detection limit