Despite longstanding concerns over pesticide contamination in aquatic environments, their impacts on nitrogen-cycling functions in agricultural soils remain inadequately explored. This study employed target, suspect, and nontarget screening to identify residual pesticides and transformation products (TPs) in rapeseed-rice rotation soils, revealing associations with ammonia-oxidizing microorganisms (AOMs). Suspect and nontarget screening uncovered an additional eight pesticides and 14 TPs, including three novel TPs and three newly identified in environmental matrices. The mean total concentration of TPs (230 μg/kg dw) was comparable to that of the parent pesticides (221 μg/kg dw) with enrichment in the rhizosphere. Ammonia-oxidizing archaea and comammox Nitrospira were more susceptible to pesticides and TPs than ammonia-oxidizing bacteria. Notably, certain TPs imposed greater stress on AOMs than their parent compounds, especially in the rhizosphere. These findings suggest that pesticide-induced shifts in AOM abundance may alter soil nitrogen cycling, highlighting the need to investigate the long-term effects on nitrogen-cycling microorganisms in agricultural soils.
Li et al. (Fri,) studied this question.