Samples from soils amended with treated wastewater or tap water from the Czech Republic. Raw sequence reads. Samples from WWT amended soils from the Czech Republic

Reusing treated wastewater for irrigation purposes in agriculture is a common but controversial practice to save freshwater and provide plants with nutrients. It often leads to a change in physico-chemical properties and the introduction of uncontrolled amounts of contaminants of emerging concern into the receiving soil. As a result, the structures and functions of microbial communities in the soil can change to an unknown extent. This study aimed to assess the effects of effluent from municipal WWTP on the abundance, diversity and composition of soil microbial communities and ammonia oxidizers in two arable soils, Arenosol Epieuric (sandy soil) and Haplic Cambisol (loam-sandy soil). Raised beds filled with soil were irrigated with tap water (W) or effluent (E) and used for vegetable crop rotation (lettuce, onions and carrots). The changes in soil chemical properties, nutrient content, abundance of ammonia oxidizers (bacteria and archaea), abundance and composition of soil bacteria and fungi were evaluated 0, 54, 115 and 152 days after the start of the experiment.