Lime-induced chlorosis

Lime-induced chlorosis is a physiological disorder occurring when plants are unable to uptake sufficient iron from the soil due to high alkalinity. This is a non-infectious condition, primarily caused by chemical interactions in the rhizosphere that render essential micronutrients insoluble and unavailable for root absorption.

A wide range of plant species suffers from this condition, particularly those growing in calcareous soils. Economically important crops such as peach trees are highly sensitive, often exhibiting severe leaf yellowing. Similarly, Linseed (common flax) shows significant physiological stress when grown in alkaline conditions, leading to reduced seed oil content and lower fiber quality.

The primary symptom is interveinal chlorosis, where the leaf tissue turns pale green or yellow while the veins remain distinctively green. As the condition progresses, the yellowing can spread to the entire leaf, eventually leading to leaf browning, necrosis, and premature defoliation. This significantly reduces the plant's photosynthetic capacity and vigor.

The development of this disorder is closely linked to soil pH. When the pH level exceeds 7.5, iron compounds precipitate and cannot be taken up by the roots. Poor drainage and soil compaction further exacerbate the issue by restricting oxygen availability to the root zone, which hampers the plant's ability to actively transport micronutrients.

The damage caused by this condition can be severe, ranging from stunted growth to the death of branches and reduced yields. Prevention and management strategies include:

• Foliar application of chelated iron (Fe-EDDHA).
• Acidification of the soil using elemental sulfur.
• Improvement of drainage and soil aeration.
• Use of iron-efficient rootstocks for susceptible cultivars.