Are mineral nutrients a critical factor for lime intolerance of lupins?

Poor growth of lupins on calcareous soils may be attributed to a number of soil physical and chemical factors. Nutrient imbalances, such as deficiency of phosphorus (P) and micronutrients or calcium (Ca) excess have been repo rted to be responsible for the calcifuge behavior of the plants. In the pre sent study we investigated the importance of nutrient imbalances for the gr owth reduction of lupins on a lime-containing soil. Three lupin species (Lu pinus luteus, Lupinus angustifolius, and Lupinus albus) were compared with lime-tolerant Pisum sativum. Plants were cultivated in a sandy soil contain ing 0.2% or 10% magnesium (Mg) limestone and were fertilized with a complet e nutrient solution except for iron (Fe). In each lime treatment, three of six pots per species were supplied with iron as FeEDDHA. Strong liming grea tly decreased shoot growth, rate of leaf appearance, and shoot dry matter a ccumulation in all Lupinus species, but only marginally in P. sativum. All Lupinus species displayed chlorosis on the strongly limed soil, whereas on the slightly limed soil, only L. luteus did so. Shoot concentrations of P, potassium (K), Ca, Mg, manganese (Mn), zinc (Zn), and copper (Cu) were gene rally in the adequate range. Decreased shoot growth was not associated with increased Ca concentrations. FeEDDHA fertilization alleviated chlorosis in most cases, but was not able to restore shoot growth. Therefore it is conc luded, that, at least in the juvenile stage, nutrient imbalances do not pla y a major role in growth limitation of lupins on calcareous soils.