Table 5.

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 antioxidant enzymes in maize leaves during the growing seasons of 2019/2020 and 2020/2021

Studied factors		SOD (μmol g−1)	POD (μmol g−1)	CAT (μmol g−1)
PRIs techniques
FDI		243.4 ± 27.7 b	98.69 ± 27.9 b	328.5 ± 67.4 a
ADI		265.7 ± 61.5 a	122.62 ± 24.3 a	325.1 ± 61.1 a
Irrigation levels (Ir)
100 (%)		242.5 ± 48.4 b	99.86 ± 31.2 b	309.5 ± 96.5 b
75 (%)		266.7 ± 45.02 a	121.5 ± 24.8 a	344.4 ± 69.5 a
Applications (EAP)
Control		225.9 ± 52.5 g	100.7 ± 28.9 i	287.4 ± 62.9 e
KH F		241.3 ± 36.6 e	106.6 ± 33.2 g	305.7 ± 76.2 d
Zn F		238.9 ± 46.3 f	103.1 ± 31.5 h	301.1 ± 63.6 d
KH S		252.5 ± 37.6 d	110.2 ± 36.2 e	325.6 ± 77.2 c
Zn S		251.7 ± 27.8 d	108.1 ± 35.5 f	323.6 ± 70.9 c
KH F + Zn F		260.5 ± 29.6 c	112.0 ± 35.7 d	332.4 ± 74.9 c
KH F + Zn S		268.6 ± 33.3 b	115.9 ± 37.8 b	345.8 ± 83.9 b
KH S + Zn F		267.7 ± 51.1 b	115.1 ± 31.2 c	350.8 ± 101.3 b
KH S + Zn S		283.9 ± 53.1 a	124.2 ± 35.6 a	368.9 ± 99.9 a
Source of variation	df	p-values
PRIs techniques	1	< 0.001	< 0.001	0.19 NS
Irrigation levels (Ir)	1	< 0.001	< 0.001	< 0.001
Examined applications (EAP)	8	< 0.001	< 0.001	< 0.001
PRIs × Ir	1	< 0.001	< 0.001	0.47 NS
PRIs × EAP	8	< 0.001	< 0.001	< 0.001
Ir × EAP	8	< 0.001	< 0.001	< 0.001
PRIs × Ir × EAP	64	< 0.001	< 0.001	< 0.001

Abbreviations: SOD Superoxide dismutase, POD Peroxidase, CAT Catalase, 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)