A tobacco-rapeseed rotation model for economically sustainable phytoremediation of cadmium-contaminated farmland.

Soil cadmium (Cd) contamination poses a persistent challenge to the sustainable management of agricultural land, as conventional remediation technologies are often costly, disruptive, and difficult to implement at scale. Although phytoremediation is environmentally friendly, its large-scale application has been constrained by the poor adaptability and low economic viability of hyperaccumulator-based models. To address this limitation, this study develops and evaluates a tobacco-rapeseed rotation (TRR) model that integrates high-biomass economic crops into a continuous, cross-seasonal remediation framework. Based on one-year field experiments combined with economic assessment and life cycle analysis, the performance of the TRR was systematically compared with representative phytoremediation pathways. The TRR achieved an average annual Cd removal of 349.91 g/ha, while exhibiting the lowest unit Cd removal cost (105.31 CNY/g) and the shortest investment payback period (26 years) among the evaluated models. Life cycle assessment revealed that the environmental burden of the TRR was primarily associated with post-harvest biomass disposal, indicating substantial potential for impact reduction through biomass valorization. Scenario analysis further demonstrated that, under low-level Cd contamination, the TRR can simultaneously ensure food safety and generate stable economic returns with manageable health risks. Overall, the TRR represents a scalable and economically self-sustaining "remediate-by-farming" strategy, offering a practical pathway for the sustainable management and safe utilization of cadmium-contaminated farmland.