Research Article
Nitrogen Immobilization in Plant Growth Substrates: Clean Chip Residual, Pine Bark, and Peatmoss
Table 4
Microbial respiration in clean chip residual, pine bark and peatmoss substrates.
| Substratez | Carbon mineralization (mg/kg) | 0 mg N | 1 mg Ny | 2 mg N | 3 mg N | MSD N-ratex |
| | | 0–7 days | | | 0.48 cm CCR | 2370 | 3236 | 3584 | 3882 | 113 | 0.95 cm CCR | 1757 | 2593 | 2987 | 3414 | 154 | PB | 1918 | 2311 | 2367 | 2478 | 111 | PM | 143 | 94 | 614 | 258 | 335 |
| MSD Substrate | 84 | 121 | 284 | 170 | |
| | | 8–15 days | | | 0.48 cm CCR | 2615 | 2827 | 2888 | 3358 | 183 | 0.95 cm CCR | 2200 | 2620 | 3105 | 3706 | 209 | PB | 1625 | 1986 | 1944 | 2021 | 329 | PM | 356 | 384 | 353 | 371 | 117 |
| MSD Substrate | 283 | 140 | 172 | 149 | |
| | | 16–30 days | | | 0.48 cm CCR | 3479 | 3615 | 3631 | 3436 | 134 | 0.95 cm CCR | 3229 | 3556 | 3728 | 3714 | 225 | PB | 2254 | 2485 | 2585 | 2586 | 129 | PM | 751 | 591 | 578 | 641 | 166 |
| MSD Substrate | 195 | 139 | 123 | 126 | |
| | | 31–60 days | | | 0.48 cm CCR | 4133 | 3812 | 3721 | 3837 | 459 | 0.95 cm CCR | 4082 | 4211 | 4041 | 3767 | 324 | PB | 2950 | 3173 | 3356 | 3417 | 190 | PM | 1723 | 1682 | 1581 | 1582 | 258 |
| MSD Substrate | 355 | 166 | 238 | 248 | |
| | | Total: 0–60 days | | | 0.48 cm CCR | 12360 | 13414 | 13778 | 14108 | 609 | 0.95 cm CCR | 11016 | 13110 | 14377 | 14624 | 799 | PB | 8954 | 10097 | 10313 | 10484 | 422 | PM | 2989 | 2922 | 2762 | 2781 | 440 |
| MSD Substrate | 668 | 405 | 662 | 409 | |
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zCCR: clean chip residual, PB: pine bark, and PM: sphagnum peatmoss.
y2000 ppm stock solution of NH4NO3 (0, 0.5, 1.0, 1.5 mL).
xMSD based on Waller-Duncan ratio -tests ( = 0.05).
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