Potential of Sugarcane Biomass-Derived Biochars for the Controlled Release of Sulfentrazone in Soil Solutions

Sugarcane bagasse-derived biochars, produced at 350 °C (B350) and 600 °C (B600), were evaluated for their capacity to modify the sorption behavior of the herbicide sulfentrazone (SFZ) in Red–Yellow Latosol (RYL) and to serve as carriers for its controlled release. Batch sorption experiments indicated that SFZ exhibits low affinity for soil and undergoes sorption–desorption hysteresis. Adding B350 biochar (up to 0.30%) did not significantly affect the herbicide sorption, whereas B600 enhanced its retention. Sequential desorption assays were conducted by incorporating SFZ either directly into the soil or into the biochars, which were subsequently blended into the soil (at 0.15% w/w). The SFZ desorbed more rapidly from the soil than from the biochars, suggesting that the pyrogenic material has potential for modulating herbicide release. Phytotoxicity assessments using Sorghum bicolor confirmed that only SFZ incorporated into B350 (at 0.15% w/w) retained herbicidal efficacy comparable to its direct application in soil. These findings underscore the potential of B350 biochar as a controlled-release carrier for SFZ without compromising its weed control effectiveness.