Changes in the Regulating Ecosystem Service on the Contaminated Site Used for Energy Purposes

Soil cleaning, the ability of the soil to immobilize the risk elements, belongs to important agroecosystem services in terms of protection of the hydrosphere and plant production from contamination. Dynamic monitoring of selected indicators of soil quality was realized in a special network of site on soil used for planting fast growing willow (Salix viminalis). Monitoring of the study site Kuchyňa (Mollic Fluvisol) is running since 2010 year. The fast-growing willow was planted on an area of about 43 hectares. Study site Kuchyňa belonged to the degraded contaminated sites, at the time of planting (the total contents of the risk elements were as follows: Cd 1.016 mg∙kg−1, Zn 199.000 mg∙kg−1, Ni 51.500 mg∙kg−1) There were positive changes in the total content of cadmium, zinc and nickel (in 2018 year), the zinc content decreased by 27% compared to 2010, the nickel content was lower by 23% and the Cd content by 57% in comparison to 2010 year, these elements have a declining trend during the monitored period. The remediation ability of the willow in relation to the risk elements was manifested by the accumulation of these elements in the wood mass and by their decrease in the soil below the limit value. The regulatory ecosystem service, the potential for the immobilisation of the risk elements, was evaluated based on the sum of the assessment of the contamination potential and the sorption potential of soil. The decrease of the total content of risk elements in the soil below the limit value was manifested in the increase of the potential of the agroecosystem regulatory service, the potential of risk element immobilisation, from very low category to medium category. If willow cultivation continued in the next decade, the value of risk element Zn would most likely reach the value 73 mg∙kg−1, which is less than 50% of the limit value, based on the results of the predictive model. In the case of Cd, the soil would be completely cleaned and in the case of Ni, its total content in the soil would fall to 23 mg∙kg−1, which is less than 40% of the limit value. The overall potential for contamination would fall into the category—very low (forecast for 2021 year). The higher potential of immobilisation reduces the risk of contaminants transport and thus prevents contamination of the other ecosystem components such as biota.