This study optimized and guayule bagasse biochar for improving ex-situ arid farm soil, focusing on stability, carbon sequestration, and soil health. Temperature was identified as the main significant variable, as higher pyrolysis temperatures increased biochar stability but reduced cation exchange capacity (CEC). Three optimized biochars were produced through slow pyrolysis: a high-temperature carbon-rich biochar (yield 34 wt%), a midtemperature biochar designed for balanced carbon retention and structural development (yield 34 wt%), and a low-temperature high-yield biochar (yield 47 wt%). These materials were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis with Derivative Thermogravimetry (TGA-DTG), and Brunauer-Emmett-Teller (BET) surface area analysis. Among the three, the mid-temperature biochar was selected as the preferred material due to its favorable oxygen-to-carbon (O/C = 0.1) and hydrogen-to-carbon (H/C = 0.4) ratios, specific surface area (0.89 +/- 0.09 m2/g), pore volume (0.0017 cm3/g), pore size (9.48 nm), and suitable carbon-to-nitrogen ratio (C/N = 10). Additionally, the mid-temperature biochar requires significantly less energy to produce. Optimal pyrolysis conditions for producing this biochar were a nitrogen flow rate of 40 mL/min, temperature of 443 degrees C, holding time of 45 min, and heating rate of 10 degrees C/min, resulting in a carbon content of 64 -70 wt%, fixed carbon of 59 +/- 1 wt%, and a mean residence time (MRT) of 1151 years, indicating high recalcitrance. The low-temperature high-yield biochar also demonstrated potential for use in acidic soils with lower CEC and poor texture, broadening the applicability of the biochar across diverse agroecosystems.