Table 1.
Soil parameters before the field experiment in 2020–2022.
| Parameter | Value |
|---|---|
| pH KCl | 6.0 |
| Available P2O5 [mg kg−1] | 243.4 |
| Available K2O [mg kg−1] | 222.2 |
| Available MgO [mg kg−1] | 70.0 |
Table 2.
Meteorological conditions in 2020–2022.
| Month | 2020 | 2021 | 2022 | |||
|---|---|---|---|---|---|---|
| Precipitation [mm] | Air temperature [°C] | Precipitation [mm] | Air temperature [°C] | Precipitation [mm] | Air temperature [°C] | |
| January | 32.0 | 2.6 | 49.2 | −1.4 | 64.0 | 0.7 |
| February | 42.1 | 3.7 | 29.4 | −2.7 | 49.0 | 3.0 |
| March | 28.1 | 4.0 | 21.4 | 3.3 | 0.5 | 2.9 |
| April | 4.2 | 8.0 | 33.2 | 5.8 | 24.5 | 6.8 |
| Mai | 44.8 | 10.8 | 68.0 | 11.6 | 24.8 | 12.9 |
| June | 165.5 | 17.7 | 40.9 | 19.1 | 39.5 | 18.3 |
| July | 57.4 | 18.2 | 45.7 | 22.5 | 42.9 | 18.8 |
| August | 104.7 | 19.7 | 34.1 | 17.1 | 63.7 | 21.2 |
| September | 55.1 | 14.5 | 25.0 | 14.0 | 54.1 | 12.1 |
| October | 70.0 | 10.1 | 24.6 | 8.8 | 28.3 | 10.3 |
| November | 12.3 | 5.7 | 33.8 | 4.9 | 19.8 | 3.6 |
| December | 35.9 | 1.6 | 25.1 | −1.4 | 31.1 | 0.7 |
| Averages | 557.9 | 9.7 | 430.4 | 8.5 | 442.2 | 9.3 |
Figure 1.
Content of nitrates in potato tubers depending on genotype and earliness group. Means sharing the same letter are not significantly different (p<0.05)
Figure 2.
Content of nitrites in potato tubers depending on genotype and earliness group. Means sharing the same letter are not significantly different (p<0.05)
Figure 3.
Relationship between nitrate and nitrite content in potato tubers of different earliness groups. Statistically significant differences in nitrate and nitrite levels among the earliness groups are annotated beside the graph. Means sharing the same letter are not significantly different (p<0.05).
Table 3.
Percentage decrease in nitrate and nitrite content in potato tubers after storage during 6 months depending on genotype and earliness group
| Earliness Group | Varieties | Nitrate [%] | Nitrite [%] |
|---|---|---|---|
| Very early varieties | Impresja | 5.4 | 17.1 |
| Surmia | 6.5 | 22.4 | |
| Tacja | 6.5 | 21.2 | |
| Average | 6.1 | 20.2 | |
| Early varieties | Baltic Fire | 7.6 | 24.4 |
| Bohun | 4.8 | 16.7 | |
| Gardena | 7.5 | 23.2 | |
| Golden Marie | 4.8 | 14.3 | |
| Ignacy | 6.3 | 22.1 | |
| Ismena | 5.5 | 19.2 | |
| Magnolia | 5.5 | 19.5 | |
| Mia | 6.6 | 22.9 | |
| Stokrotka | 7.5 | 22.8 | |
| Wega | 5.4 | 17.2 | |
| Average | 6.1 | 20.2 | |
| Medium-early varieties | American Rose | 8.3 | 23.8 |
| Baltic Rose | 5.7 | 17.2 | |
| Jurek | 5.8 | 17.3 | |
| Mazur | 6.5 | 19.7 | |
| Tajfun | 8.4 | 23.8 | |
| Average | 6.9 | 20.3 |