Iron deficiency

Iron deficiency is a common physiological disorder that acts as a major limiting factor in plant development. Although it is not caused by a biological pathogen, its impact on plant physiology mimics the damage of infectious diseases, often resulting in significant economic losses in horticulture and large-scale agriculture.

The characteristic visual symptom is interveinal chlorosis, which primarily affects young leaves. The leaf tissue turns yellow while the vascular veins remain dark green. As the deficiency progresses, the entire leaf may turn white (bleaching), eventually resulting in necrotic lesions, leaf drop, and stunted growth of the entire plant canopy.

Biologically, iron is a critical component for chlorophyll synthesis and the function of various enzymes involved in the electron transport chain during photosynthesis. When a plant cannot mobilize sufficient iron, its photosynthetic capacity drops drastically, disrupting the internal energy balance and metabolic pathways essential for vegetative and reproductive growth.

Development and spread are primarily driven by soil conditions, most notably high pH levels. In calcareous or alkaline soils, iron becomes chemically unavailable to roots because it precipitates into insoluble hydroxides. Additionally, factors like waterlogging, high levels of competing metal ions (such as copper or manganese), and excessive phosphate application can exacerbate the onset of deficiency.

Effective management and control strategies focus on increasing iron bioavailability:

• Application of iron chelates (such as Fe-EDDHA or Fe-EDTA) via foliar sprays or fertigation.
• Soil acidification to lower the pH and improve nutrient uptake.
• Improving soil drainage and aeration to support root function.
• Selecting plant varieties or rootstocks that exhibit high efficiency in iron uptake.