Parameter | Influence of test setup on mineralization rates (Test series 1) | ||
---|---|---|---|
Variations in test setup | (i) Flow-through vs. semi-static | (ii) Slow flow vs. fast flow | (iii) Low vs. high amount of manure |
Details | Flow-through: 50–200 mL min−1 Semi-static: purged once/week | Slow flow: 50–200 mL/min Fast flow: > 200 mL min−1 | Low: 50 g manure fw High: 300 g manure fw (slow flow-through) |
Test substance | 14C-salicylic acid | 14C-salicylic acid | 14C-salicylic acid |
Temperature | 20 ± 2 °C | 20 ± 2 °C | 20 ± 2 °C |
Light | Darkness | Darkness | Darkness |
Acclimation period | 21 days | 21 days | 21 days |
Type of manure | Cattle (c), pig (p) | Cattle (c), pig (p) | Cattle (c), pig (p) |
Manure sampling | 1 site: summer (c, p) | 1 site: winter (c, p) | 1 site: winter (c, p) |
Dry matter content | 10 ± 1% (c), 5 ± 1% (p) | 10 ± 1% (c), 5 ± 1% (p) | 10 ± 1% (c), 5 ± 1% (p) |
Amount of manure | 50 g fw | 50 g fw | 50 g fw or 300 g fw |
Replicates per sampling | 6 (set in parallel) | 6 (set in parallel) | 6 (set in parallel) |
Test duration | 85 days (c, p) | 91 days (c), 85 days (p) | 91 days (c), 85 days (p) |
Sampling time points | c: 3, 7, 14, 21, 35, 42, 49, 56, 63, 85 p: 3, 7, 14, 21, 35, 42, 49, 56, 63, 85 | c: 3, 7, 14, 21, 29, 35, 42, 49, 56, 63, 70, 79, 91 p: 3, 7, 14, 21, 35, 42, 49, 56, 63, 85 | c: 3, 7, 14, 21, 29, 35, 42, 49, 56, 63, 70, 79, 91 p: 3, 7, 14, 21, 35, 42, 49, 56, 63, 85 |
14CO2/14CH4 quantification | Yes (each sampling point) | Yes (each sampling point) | Yes (each sampling point) |
Residue characterization | Yes (at the end) | Yes (at the end) | Yes (at the end) |
Abiotic/sterile controls | No | No | No |
Microbial activity testing | Yes (at start and end) | Yes (at start and end) | Yes (at start and end) |
Complete mass balance | Yes (at the end) | Yes (at the end) | Yes (at the end) |
Evaluation of kinetics | Yes (mineralization rate, DT50 MIN) | Yes (mineralization rate, DT50 MIN) | Yes (mineralization rate, DT50 MIN) |