Rising fertilizer costs and dwindling freshwater supplies are driving interest in alternative agricultural amendments, including biosolids and reclaimed water. Although these inputs can promote crop growth, they also contain organic contaminants of concern, including polyfluoroalkyl substances, which may affect plants directly or indirectly via changes to plant-associated microbiomes. We conducted two greenhouse experiments to evaluate the direct and microbially mediated effects of biosolid and reclaimed water amendments spiked with increasing contaminant concentrations on lettuce ( Lactuca sativa), radish ( Raphanus sativus), and green pea ( Pisum sativum). Peas exhibited pronounced negative responses to biosolids, including reduced germination, survival, and biomass, which scaled with contaminant concentration and coincided with visible pathogen infection. In contrast, lettuce and radish showed minimal impact, suggesting that species-specific differences in microbial associations and nutrient acquisition strategies may influence susceptibility to contaminant-induced stress. Soil bacterial microbiome diversity generally recovered over time, whereas bacterial community composition often exhibited persistent crop- and amendment-specific shifts. However, microbiomes shaped by prior exposure had limited effects on pea performance when transferred to new plants in the absence of ongoing stressors. These findings suggest that persistent changes in bacterial community composition do not necessarily translate into equivalent functional consequences for plant growth and that current soil conditions may outweigh microbiome legacy effects. Overall, our results demonstrate that crop identity strongly mediates amendment impacts and highlight the importance of considering functional trait variation when evaluating the risks and benefits of wastewater-derived amendments. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
