Responses of peanuts to iron‐manganese interaction in calcareous soil

Abstract

Iron‐Mn interactions in plant nutrition have been documented, but are not fully understood. The objectives of this study were to determine the responses of peanuts (Arachis hypogaea L.) to Fe‐Mn interactions during growth in a calcareous soil.

Sixteen combinations of FeEDDHA and MnSO₄ were used as treatments in a pot experiment. At 10, 31 and 60 days after emergence plant tops were harvested, their dry weights recorded and Fe, Fe²⁺, Mn and chlorophyll concentrations determined. Second order polynomial regression models were developed and visualized by means of equidistant surfaces.

The results indicated that Fe‐Mn interactions occur at two levels: at uptake level, where Fe hampers manganese uptake, and at metabolic level, where Mn₂₊ inactivates Fe metabolic activity by decreasing Fe concentration in plants. In order to avoid nutrient imbalance, it is necessary to regulate Fe and Mn nutrition of peanuts when grown in calcareous soil.

Key words:

• Calcareous soil
• Arachis hypogaea L
• Fe chlorosis
• Mn toxicity
• Fe efficiency
• Fe‐Mn balance
• Bivalent iron
• FeEDDHA