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Table 5 Critical levels of macro and micronutrients with different soil tests as reported by different authors

From: Soil fertility status and wheat nutrient content in Vertisol cropping systems of central highlands of Ethiopia

Elements

Method used

Critical levels

References

P

Olsen

10–17 mg kg−1

[32]

K

NH4OAc, pH = 7

0.3–0.7 cmol kg−1

[47]

Ca

NH4OAc, pH = 7

5–10 cmol kg−1

[47]

Mg

NH4OAc, pH = 7

1–3 cmol kg−1

[47]

Sulfate-S

CaCl2

5 mg kg−1

[55]

Cu

AB-DTPA

0.5 mg kg−1

[56, 57]

Fe

AB-DTPA

5 mg kg−1

[56, 57]

Mn

AB-DTPA

1 mg kg−1

[56, 57]

Zn

AB-DTPA

1.5 mg kg−1

[56, 57]

Mo

AAO

0.1–0.5 mg kg−1

[35, 58]

B

Mehlich 3

0.5–1 mg kg−1

[58, 59]

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Agriculture & Food Security

ISSN: 2048-7010