Sulfonamides (SAs) are one of the most frequently used antibiotics in the veterinary industry, showing high mobility in soils. Objectives of this research were to determine sorption, distribution coefficients and involvement of different ionic forms of sulfamethazine (SMZ), a representative SAs, and to evaluate transport and plant uptake of SMZ in biochar treated soils. Biochars were produced from invasive plant, burcucumber (Sicyos angulatus L.), under slow pyrolysis conditions at peak temperatures of 300 ⁰C (biochar-300) and 700 ⁰C (biochar-700), respectively. The abilities of the biochars to retain SMZ in loamy sand and sandy loam soils were examined under different pHs and SMZ loadings. Column transport experiments showed that biochar-700 had a high degree of SMZ retention, with resultant decreased pH in both soils. Modeled effective sorption coefficients (K_D,eff) values indicated that the observed high SMZ retention at pH 3 could be attributed to the p-p electron donor-acceptor interaction and electrostatic cation exchange, whereas at pH 5 and 7, cation exchange was the main mechanisms responsible. There was no temporal retardation of SMZ in biochar treated soil as compared to the untreated soil. However, biochar-700 treatment achieved up to 89% and 82% increase in the SMZ retention in sandy loam and loamy sand soils, respectively. With 5% BBC700, the plant uptake of SMT was reduced by 86% in the soil spiked with 5 mg kg^-1 SMT compared to the control whereas a 63% reduction was observed in the soil spiked with 50 mg kg^-1 SMT. Application of BBC700, into soils effectively reduced the SMT uptake by lettuce. The overall results demonstrated that burcucumber biochar produced at higher temperature was effective in reducing the mobility and plant uptake of SMZ in the studied soils. This research was supported by the Basic Science Research Program, through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (Project number: 2015R1A2A2A11001432).