Micronutrient inflow rates and mobilisation into soil solution in the root zone of winter wheat (Triticum aestivum L.)

Concentrations of Cu, Mn and Zn in root-zone soil solutions were determined for a field-grown winter wheat crop, and their inflow rates were calculated. This latter parameter was highest in mid-July. Depletion rates of the root-zone soil solution were calculated for Cu, Mn and Zn. Although calculated depletion rates indicated adequate early season levels of micronutrients, these reserves were depleted more rapidly than could be explained by plant uptake. The size of the soil solution reservoir of micronutrients appears to depend on the balance between mobilisation and immobilisation which in turn depends on the flux of biologically produced chelating ligands.