Hyphomicrobiales-mediated C-S coupling underpins enantiomeric differences in soil nutrient cycling induced by the...

Chiral herbicides are widely used in agriculture, yet their enantiomer-specific effects on soil nutrient cycling remain poorly understood. Here, we investigated the enantioselective impacts of R- and S-napropamide (NAP) on the dynamics of mineral nutrient elements and the associated potential driving mechanisms across four soil types. Our findings revealed significant enantiomer-specific differences in soil nutrient profiles following NAP treatment. Physicochemical factors, including pH, total carbon, and dissolved organic nitrogen, were closely associated with the status of metallic nutrients. In turn, these factors were linked to the dynamics of non-metallic elements through potential microbial processes. In-depth analysis revealed significant enantiomer-dependent differences in the correlations between dissolved organic carbon and the relative abundance of key functional genes involved in methane metabolism, organic carbon oxidation, organic sulfur mineralization, and sulfate oxidation/reduction. Crucially, R-NAP maintained a synergistic carbon-sulfur coupling pattern potentially linked to nitrogen cycling, whereas S-NAP suggested a functional decoupling, shifting the system into a carbon-driven compensatory mode. These findings provide a novel ecological perspective on understanding how chiral herbicides differentially influence soil nutrient networks, offering critical insights for environmental risk assessment and sustainable herbicide management strategies that protect soil ecosystem functions.