REGULARITIES OF MIGRATION 137CS IN THE ALLUVIAL SOIL

This paper examines the patterns of 137 Cs migration in the alluvial soil of the central floodplain of the Iput River (Novozybkovsky district, Bryansk region). The effect of water filtration during flooding, bioremoval by plants and 137 Cs radioactive decay on the migration process of Cs ions in the soil was studied. The contribution of radioactive decay, filtration of water and bioremoval to the total removal of 137 Cs from the soil during the period from 1994 to 2007 was 50–79, 20–50, 0.3–2.2 % coorespondingly, depending on the treatment method, the dose of mineral fertilizers and the ratio of nutrients. It was found that the increased removal of 137 Cs from the soil layer of the floodplain during double-depth plowing, compared with disking and natural grass stands, is determined by a lower Peclet number, which indicates the prevalence of convective 137 Cs transfer in contrast to diffusion in the total solution flow.