The movement of Cesium 137 (¹³⁷Cs) in soil varies depending on physio-chemical properties of soil, soil microbial activities, plant species and climatic conditions. The entry of ¹³⁷Cs into the food-chain can be minimized the choice of plants, soil amendments and agronomic practices. Organic compost binds metals and prevent their uptake to plants, thereby preventing transfer of metals from contaminated soil into the food chain. Plant growth-promoting rhizobacteria (PGPR) are also of interest for application in agriculture as bio-fertilizers or as pesticides as well as for phytoremediation techniques to decontaminate soils and waters. Thus, this study was carried out to assess the possible influences of organic compost and PGPR on ¹³⁷Cs movement in soil-plant systems.

The experiment was conducted at Nihonmatsu City, Fukushima Prefecture during June to August 2012. The ¹³⁷Cs content of the study soil ranged from 1609 to 2322 Bq kg^-1. The soil amendment treatments included ii) No soil amendment, ii) No organic amendment but with PGPR, (iii) Organic compost (0.5 kg m^-2), (iv) Organic compost (0.5 kg m^-2) and PGPR, (v) Organic compost (1 kg m^-2), (vi) Organic compost (1 kg m^-2) and PGPR. The cruciferous crops tested were two kinds of leafy vegetable komatsuna and mustard and two kinds of root vegetable Japanese radish and turnip.

The water soluble fraction and ion exchangeable fraction were less than 10%, while fraction fixed to clay were more than 50%. Compost amendment alone increased growth and total ¹³⁷Cs uptake, while reducing the content. PGPR application alone did not promote growth but increased the ¹³⁷Cs content as well as total uptake. The combination of compost and PGPR increased the plant growth and reduced the ¹³⁷Cs content and total ¹³⁷Cs uptake. The use of organic materials should be further investigated on the fate of ¹³⁷Cs contained in the organic fraction.