Long-term effects of potassium chloride, wood ash, and EDTA on 137Cs soil-plant transfer in a mixed forest of Ukraine

We conducted a 10-year field experiment to study the effects of potassium chloride, wood ash, zinc, and manganese on reducing ¹³⁷Cs uptake by young leaves and green shoots of common dwarf shrubs and tree species near the Chornobyl Nuclear Power Plant. A field experiment had four treatments: a control with no fertilisation, and three fertilised treatments: potassium fertiliser (KCl), a combination of potassium fertiliser and wood ash (KCl + Ash), and a solution providing zinc and manganese (EDTA). There was approximately 30 % decrease in ¹³⁷Cs uptake by most of the studied plants species growing on plots fertilised with KCl compared to unfertilised plots during intermediate (2014-2016) and late (2018-2021) periods. Combining KCl with wood ash was found to be the most effective countermeasure, reducing ¹³⁷Cs uptake by up to 60% in most species, while treatment with EDTA was less effective. Generally, the decline in ¹³⁷Cs uptake by plants over the study years following treatments with fertilisers was more pronounced than in the control, indicating the efficiency of fertilisation in reducing ¹³⁷Cs uptake by forest plants. Our research suggests that a combination of potassium chloride and wood ash can still effectively reduce ¹³⁷Cs transfer in most common forest species, even years after the accident.