Which soil condition leads to chlorosis due to iron deficiency?

• A. Soils with a high pH and calcium carbonate (limestone).
• B. Very acidic soils.
• C. Very sandy soils with low water.
• D. Soils rich in organic matter.

Answer: (A)

Iron deficiency chlorosis shows up when iron becomes insoluble and unavailable to plant roots, which happens when the soil pH is high. Soils with calcium carbonate (limestone) raise the pH, causing iron to precipitate as insoluble compounds. Even if iron is present, plants can’t uptake enough, so chlorophyll synthesis is impaired and the leaves turn yellow, especially in the new growth, with interveinal yellowing.

In very acidic soils, iron stays soluble, so this particular deficiency is unlikely to occur there. Very sandy, drought-prone soils limit overall nutrient uptake but don’t create the same iron availability problem caused by high pH. Soils rich in organic matter often improve iron availability through natural chelation, reducing the risk of chlorosis.