Critical levels of iron, manganese and zinc in Egyptian soils

Abstract

Pot experiments were conducted to evaluate the critical levels of Fe, Mn and Zn in different Egyptian soils. Diethylenetriamine‐pentaacetic acid (DTPA) extractable Fe, Mn, and Zn were positively correlated with their concentration in leaves of maize (Zea mays L.) plants grown on the soils with and without added Fe, Mn, and Zn applied as ethylenediaminetetraacetate (EDTA) salts. Correlations were significant for Zn only. Using the DTPA extractable method, the suggested critical levels of Fe in the alluvial, sandy, and calcareous soils were 5.6, 3.4, and 3.8 mg kg^‐1, respectively. The suggested critical,levels of Mn in sandy and calcareous soils were 1.4 and 1.2 ug g^‐1, respectively. Critical levels of Zn in the alluvial and calcareous soils were 0.9 and 0.7 ug g^‐1, respectively, but no critical value was detected for the sandy soil.

Key words:

• Critical levels
• Alluvial
• Calcareous and sandy soils
• Maize
• DTPA extract
• Zea mays