• • DGT-derived effective concentrations (CE) showed significant positive correlations with sulfonamide concentrations in plant tissues (P < 0.05), confirming DGT's superior predictive ability for plant uptake compared to soil solution and solvent extraction methods.
• • DIFS model fitting yielded soil-water partition coefficients (Kdl) ranging from 0.23 to 1.25 mL·g−1, with higher Kdl values indicating greater bioavailability; this parameter is critical for predicting antibiotic mobility and plant uptake in agricultural soils.
• • Response times (Tc) for the four sulfonamides ranged from 2307 to 7523 seconds, with sulfamethoxazole (SMZ) showing the highest Tc, indicating its desorption from soil solids is kinetically limited, which may reduce its immediate bioavailability but prolong its persistence.
• • The non-linear increase in DGT-adsorbed mass over time demonstrated that solid-phase resupply is the dominant mechanism sustaining long-term DGT uptake, highlighting the importance of desorption kinetics in assessing long-term bioavailability and leaching risks.