Table 3. Degradation rate of three pesticides at different concentrations after 90 days of white trifoliate silage fermentation.
| Pesticide types | Pesticide concentration | The initial concentration, mg/kg | Residual concentration, mg/kg | Detection limit, mg/kg | Degradation rate, % | Recovery rates mean, % |
|---|---|---|---|---|---|---|
| chlorpyrifos | RU− | 9.38 | 4.90±0.09b) | 0.02 | 47.76±0.94b) | 77–95 |
| RU | 14.06 | 7.00±0.22a) | 50.21±1.56b) | |||
| RU+ | 18.76 | 6.60±0.23c) | 64.82±1.21a) | |||
| tebuconazole | RU− | 5.63 | 1.55±0.13b) | 0.00056 | 72.47±2.35b) | 87–101 |
| RU | 7.5 | 1.48±0.13b) | 80.27±1.73a) | |||
| RU+ | 9.38 | 1.99±0.12a) | 78.78±1.38a) | |||
| beta-cypermethrin | RU− | 5.63 | undetected | 0.003 | >99% | 72–87 |
| RU | 7.5 | undetected | >99% | |||
| RU+ | 9.38 | undetected | >99% | |||
| TCP | RU− | — | 0.2530a) | 0.00056 | — | 91–101 |
| RU | 0.1720b) | |||||
| RU+ | 0.0525c) | |||||
| 3-PBA | RU− | — | undetected | 0.2 | — | 59–77 |
| RU | undetected | |||||
| RU+ | undetected |
Note: The data are the mean±S.D. (n=3). There are differences in the mean values of a)–b) in the same column of the same pesticide with different superscripts (p<0.05). CON=control, no pesticide added; RU=Recommended usage; RU−=Less than the recommended usage; RU+=Greater than recommended usage; TCP=Chlorpyrifos toxic metabolite 3,5,6-trichloro-2-pyridinol; 3-PBA=Beta-cypermethrin toxic metabolite 3-phenoxybenzoic acid.