<p>Dielectric barrier discharge (DBD) plasma technology holds great potential for soil remediation. However, the coupling mechanisms among plasma kinetics, soil properties, and chemical additives remain unclear. This study developed a numerical model integrating nanosecond-scale discharge, second-scale radical reactions, and pollutant migration over minutes to hours, analyzing the effects of pH, porosity, soil thickness, and ionic additives (CO₃²⁻, Fe²⁺) on atrazine degradation. Simulation results indicate that CO₃²⁻ competitively consumes hydroxyl radicals (⋅OH), reducing their concentration while promoting ozone (O₃) formation, thereby altering the degradation pathway. Fe²⁺ catalyzes ⋅OH generation via Fenton-like reactions, achieving maximum degradation efficiency at pH ≈ 8.5–9.0 and Fe²⁺ = 5 × 10⁻³&#xa0;mol/m³, whereas excessive Fe²⁺ (&gt; 0.01&#xa0;mol/m³) consumes radicals, diminishing degradation effectiveness. Long-term analysis reveals that the inhibitory effect of CO₃²⁻ stabilizes over time, whereas the enhancement effect of Fe²⁺ is more pronounced in the initial phase. Soil porosity and thickness determine plasma penetration depth, thereby influencing long-term degradation efficiency. This study elucidates the short-term and long-term effects of CO₃²⁻ and Fe²⁺ on atrazine degradation, highlighting the critical role of soil structure in long-term remediation and providing theoretical guidance for optimizing DBD plasma remediation technology.</p> Graphical Abstract <p>Here is a visually compelling infographic highlighting the breakthrough research in DBD plasma soil remediation. It includes the key elements of the study, such as the effects of CO₃²⁻ and Fe²⁺ ion additives on atrazine degradation, and visually presents the impact of soil heterogeneity, plasma chemistry, and free radical reactions. This infographic can help in clearly communicating the research findings.</p> <p></p>