Nematodes as indicators of soil health in amendment-assisted remediation of contaminated soils

Abstracts Land contamination by potentially toxic elements, petroleum hydrocarbons, pesticides, and other pollutants represents a major environmental challenge that affects soil health and ecosystem functioning. Amendment-assisted phytoremediation using perennial energy crops has emerged as a promising strategy for restoring contaminated and marginal lands, while soil nematodes are increasingly recognized as sensitive indicators of ecological disturbance and recovery. A comprehensive analysis of published studies was conducted to evaluate nematode responses to potentially toxic elements and hydrocarbons in phytoremediation systems amended with biochar and ash, with particular attention to nematode abundance, diversity, trophic structure, and ecological indices. The review also examined systems involving perennial energy crops, especially Miscanthus × giganteus. Available evidence indicates that nematode responses to contaminants and amendments are strongly context-dependent and influenced by contaminant type, concentration, soil properties, amendment characteristics, and vegetation system. Bacterivorous nematodes frequently exhibit greater tolerance to contamination, whereas omnivores and predators are generally more sensitive indicators of ecological disturbance. Biochar commonly suppresses plant-parasitic nematodes while having variable effects on other trophic groups, depending on feedstock type and application rate. Ash amendments may also exhibit nematicidal effects but can negatively affect community balance at high application rates. In systems involving Miscanthus × giganteus , amendment-induced shifts in nematode communities reflect both soil recovery processes and persistent ecological disturbance. Therefore, nematode communities provide valuable insight into soil ecological functioning and remediation efficiency and represent informative bioindicators for assessing the sustainability of amendment-assisted phytoremediation strategies in contaminated soils.