Study of phosphate species of chernozem and sand soils by heterogeneous isotope exchange with 32P radioactive tracer

Weakly and tightly sorbed phosphate species on chernozem and humus sand are investigated by radioactive tracer method using ³²P. The comparison of the heterogeneous isotope exchange of ³²P-labeled phosphate of non-radioactively incubated soils and desorption of ³²P-labeled phosphate of radioactively incubated soils shows the transformation of weakly sorbed species to tightly sorbed ones. The quantity of weakly sorbed phosphorus and the steady state phosphorus exchange rate between soil and soil solution, transformation half-life of weakly to tightly sorbed phosphate are calculated.

Study of fast and slow consecutive processes by heterogeneous isotope exchange using P-32 radiotracer

The sorption of phosphate on soils is studied by radioisotopic tracer method. Two consecutive processes with rather different rates were differentiated: namely the heterogeneous isotope exchange between the phosphate in the soil solution and the weakly sorbed phosphate (fast reaction), and the transformation of weakly sorbed phosphate to tightly sorbed phosphate (slow reaction). In this paper, it is shown how the rate constants of these two processes can be determined by a radiotracer with a relatively short half-life.