Poor soil aeration or excess soil CaCO₃ induces Fe deficiency in lupins

Abstract

The poor growth and chlorosis suffered by lupins when grown on fine-textured alkaline soils appears primarily related to Fe deficiency which is affected by the level of HCO3-; and CaCO3 in the soil.Plants of Lupinus angustifolius were grown on an alkaline, sandy clay loam which was either acidified or limed. Additionally, plants received either adequate water (field capacity) or excess water to adjust the aeration of the soil.Plant growth was closely related to the concentration of Fe within the young leaves. Liming the soil or watering above field capacity reduced the Fe concentrations in shoots, induced chlorosis and reduced growth. Chlorosis and reduced growth was not caused by Mn deficiency, even though treatments that reduced growth also reduced Mn concentrations in shoots.The lime chlorosis disorder in lupins therefore is primarily caused by an inability of the plants to obtain Fe in calcareous soils and not caused by Mn deficiency or by inactivation of Fe within the shoots.