A 4 year experiment is set up to measure fixation rate of Cu, Zn, Ce and Zn in soils. Fixation rates are measured by isotope dilution. Soils include natural soils differing in pH, organic matter content and weathering stages of oxides. Synthetic soils are included containing warious types of oxides, pH and different organic matter contents. Plant uptake of metals is measured at various intervals using L value methodology.