Table 4.
The solitary effects of adopting water stress and applying different applications methods of potassium humate and zinc applications under partial root-zone drip irrigation techniques on soil pH, proline, hydrogen peroxide, carbohydrate, chlorophyll, and leaf water content in maize leaves during the growing seasons of 2019/2020 and 2020/2021
| Studied factors | Soil pH | Proline (μmol g−1) |
H2O2 (μmol g−1) |
Carbohydrate (mg g−1) |
Chlorophyll (mg g−1) |
LWC (%) |
|
|---|---|---|---|---|---|---|---|
| PRIs techniques | |||||||
| FDI | 7.28 ± 0.1 a | 108.7 ± 22 a | 29.98 ± 11.3 a | 526.3 ± 3.3 b | 48.6 ± 12.4 b | 72.37 ± 9.1 b | |
| ADI | 7.13 ± 0.08 b | 102.3 ± 34 b | 25.12 ± 11.9 b | 621.4 ± 3.7 a | 53.21 ± 11.0 a | 77.48 ± 6.4 a | |
| Irrigation levels (Ir) | |||||||
| 100 (%) | 7.18 ± 0.08 b | 97.4 ± 30.8 b | 24.84 ± 12.2 b | 539.5 ± 3.9 b | 51.27 ± 10.6 a | 77.09 ± 6.0 a | |
| 75 (%) | 7.23 ± 0.2 a | 113.6 ± 20 a | 30.26 ± 10.5 a | 608.2 ± 3.1 a | 50.49 ± 13.9 b | 72.76 ± 10.2 b | |
| Applications (EAP) | |||||||
| Control | 7.27 ± 0.22 a | 94.5 ± 18.4 h | 23.26 ± 9.9 g | 511.3 ± 1.9 h | 44.2 ± 8.1 g | 70.07 ± 10 h | |
| KH F | 7.233 ± 0.2 bc | 96.2 ± 16.3 g | 22.82 ± 6.8 g | 532.8 ± 1.4 g | 48.6 ± 4.5 e | 72.47 ± 9.9 g | |
| Zn F | 7.23 ± 0.2 b | 94.7 ± 20.6 h | 21.05 ± 6.6 h | 540.9 ± 0.52 f | 47.8 ± 7.8 ef | 72.22 ± 7.7 g | |
| KH S | 7.19 ± 0.15 d | 96.9 ± 19.3 f | 25.83 ± 10.1 f | 570.9 ± 2.03 e | 50.17 ± 5.0 d | 74.89 ± 7.7 e | |
| Zn S | 7.22 ± 0.2 c | 100.6 ± 19.4 e | 27.98 ± 12.5 d | 570.9 ± 0.35 e | 47.2 ± 4.5 f | 73.3 ± 7.8 f | |
| KH F + Zn F | 7.20 ± 0.23 d | 106.0 ± 23.7 d | 36.8 ± 5.9 a | 633.5 ± 1.24 a | 50.94 ± 6.06 d | 75.69 ± 6.4 d | |
| KH F + Zn S | 7.18 ± 0.18 e | 109.5 ± 28.6 c | 33.23 ± 5.04 b | 595.3 ± 0.52 d | 53.46 ± 13.6 c | 77.34 ± 5.3 c | |
| KH S + Zn F | 7.17 ± 0.15 e | 114.6 ± 20.9 b | 30.03 ± 8.4 c | 606.3 ± 0.46 b | 56.2 ± 9.5 b | 78.45 ± 5.6 b | |
| KH S + Zn S | 7.14 ± 0.16 f | 122.0 ± 37.6 a | 26.95 ± 6.5 e | 602.7 ± 0.32 c | 59.3 ± 13.3 a | 79.82 ± 4.5 a | |
| Source of variation | df | p-values | |||||
| PRIs techniques | 1 | 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Irrigation levels (Ir) | 1 | < 0.001 | < 0.001 | < 0.001 | 0.001 | < 0.001 | < 0.001 |
| Examined applications (EAP) | 8 | < 0.001 | < 0.001 | < 0.004 | < 0.001 | < 0.001 | < 0.001 |
| PRIs × Ir | 1 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| PRIs × EAP | 8 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Ir × EAP | 8 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| PRIs × Ir × EAP | 64 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
Abbreviations: H2O2 Hydrogen peroxide, LWC Leaf water content, PRIs Partial root-zone drip irrigation techniques, FDI Fixed partial root-zone drip irrigation, ADI Alternate partial root-zone drip irrigation. control (tap water applications), KH F (foliar applications of potassium humate = 3 g L−1 water), Zn F (foliar applications of chelated zinc = 1.25 kg ha−1), KH S (applications of potassium humate applied through the drip irrigation systems = 3 g L−1), Zn S (chelated zinc applied through the drip irrigation systems at a rate of 1.25 kg ha−1)