Long-term effects of potassium chloride, wood ash, and EDTA on Cs 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 Cs 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 Cs 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 Cs uptake by up to 60% in most species, while treatment with EDTA was less effective. Generally, the decline in Cs 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 Cs uptake by forest plants. Our research suggests that a combination of potassium chloride and wood ash can still effectively reduce Cs transfer in most common forest species, even years after the accident.