Table 2.
Seasonal Differences in Nitrate Levels Regarding Vegetable Type at All Locations Together
| Sample type: all locations together | N | Arithmetic mean | SD | Standard error | t | P | |
|---|---|---|---|---|---|---|---|
| Lettuce | Nitrate content in mg/kg in spring | 20 | 703.74 | 500.59 | 111.94 | -3.32 | 0.004 |
| Nitrate content in mg/kg in autumn | 20 | 1264.85 | 711.80 | 159.16 | |||
| Spinach | Nitrate content in mg/kg in spring | 20 | 706.28 | 432.29 | 96.66 | -6.4 | <0.001 |
| Nitrate content in mg/kg in autumn | 20 | 2013.15 | 793.12 | 177.35 | |||
| Kale | Nitrate content in mg/kg in spring | 20 | 603.03 | 444.03 | 99.29 | -4.36 | <0.001 |
| Nitrate content in mg/kg in autumn | 20 | 1181.47 | 699.55 | 156.42 | |||
| Chard | Nitrate content in mg/kg in spring | 20 | 972.24 | 697.41 | 155.94 | -0.24 | 0.814 |
| Nitrate content in mg/kg in autumn | 20 | 1024.77 | 878.75 | 196.49 | |||