Iron chlorosis induced by high copper and manganese supply

In acidic soils heavily enriched with Cu by cultivation of hop and vine, succeeding crops such as oats, kidney beans, and oil radish showed strong iron‐deficiency‐chlorosis; however, no deficiency symptoms were found in barley. A high supply of Mn from the soil combined with a high Cu content evidently inhibits iron‐uptake in Fe‐sensitive plants. Concentrations of total iron cannot sufficiently explain these observations. By carefully liming the soil and thus increasing immobilization of heavy metals, Fe‐chlorosis disappeared completely (even at lower concentrations of total iron). The differences in response by some crops might be explained by a different excretion of protons or chelating compounds, or maybe by different root systems.