Variable element transfers from an illite-rich substrate to growing plants during a three-month experiment

► Plants were grown during three months in an illite substrate in the laboratory. ► During initial growth, the elements are taken up by particle-surface ion exchanges. ► After one month, ion complexation interacts with organics released by plant roots. ► Changes in Ca/Sr and K/Rb ratios reflect enzyme activity in the element transfers. ► A positive Eu anomaly points to enzyme activity and/or anoxic conditions next to roots.