The present study aimed to evaluate the effects of titanium dioxide nanoparticles (T: 1 and 3%), sheep manure biochar (B: 1 and 3%), and their combination (T0. 5% + B0. 5% and T1. 5% + B1. 5%) on the degradation/sorption of methylene blue (MB: 100, 200, and 300 mg/kg soil) in sandy loam (SL) and loam (L) soils with variable light radiation (ultraviolet(UV) and visible(VS)). According to the results, the application of T (especially with UV radiation exposure), B, and their combination significantly reduced the MB concentration in the soils compared to the control treatment (without T and B). In addition, the combined application of T and B (T1. 5% + B1. 5%) was significantly more efficient than the other treatments in the reduction of the MB extraction in the studied soils. However, B and T application decreased the soil MB concentration, but due to the competition between the ions in the soils and MB for adsorption on the B and T surfaces, insufficient water in the soils to form appropriate amounts of degradable hydroxyl radicals, low absorption of UV radiation by T (due to the high thickness of the soil layer), and consumption of large amounts of T for soil organic matter degradation, the efficacy of these amendments decreased. Moreover, lack of using specialized biochar for this cationic contaminant (modification of the B functional groups) diminished the efficiency of this adsorbent in the soil, which requires further investigations. . .