Determination of the effects of irrigation with recycled wastewater and biochar treatments on crop and soil properties in maize cultivation

The study was conducted under two water qualities (fresh water (FW), recycled wastewater (RWW)) and two biochar treatments (no biochar (No-B) and biochar (B)). It was determined that B reduced the actual evapotranspiration by saving irrigation water and that biomass yield increased in RWW and B; thus, RWW and B provided higher WPirrigation and WP. RWW and B increased OM, TN, P2O5, K2O, CEC, porosity, and aggregate stability, thus encouraging the development of the physical–physiological properties, ADF-NDF content, and biomass yields of the crop, but causing EC to increase. RWW and B resulted in higher macro–microelement contents and heavy metal (HM) contamination in the soil; thus, increases were observed in the macro–microelements and the HM content of the crop grown in RWW and B, but the absorption and buffering capacity of B limited the Na–Cd–Cr–Ni uptake of maize. However, the HM contents of the soil–crop did not exceed international standards in all treatments except the Cd content of maize. It was found that the use of B in irrigation with RWW can be recommended, considering the productivity-increasing contribution and the effectiveness of B in reducing the possible HM risks of RWW in maize cultivation, but monitoring the Cd content of maize and the EC of the soil.