Effective dryland agriculture relies on conservation tillage, which reduces erosion and improves plant growth by preserving surface residues and maintaining soil roughness. This study was conducted in Khomein region, Iran, on clay loam soil. In this research, the influence of forward speed variables (5-10 km h(-1)) and tillage depth (17.5-27.5 cm) on chisel plow tillage quality indices was investigated. The studied indices included crop residue burial percentage and soil surface roughness and experiments were designed using response surface methodology with a central composite design. Achieving optimal tillage quality, with a focus on minimizing crop residue burial and maximizing soil surface roughness, was set as the primary objective. To quantify soil surface roughness and estimate the percentage of buried crop residues, a pin meter measuring device and image processing techniques were employed. Statistical analysis revealed that all independent variables had a significant impact on both studied indices (p < 0.01). The study results demonstrated that increasing both forward speed and tillage depth led to an increase in soil surface roughness and the percentage of buried crop residues. To enhance tillage quality and consider operational constraints, the optimal settings for plowing were determined to be a speed of 5.88 km h(-1) and a depth of 19.29 cm. Under these optimized conditions, the predicted values for soil surface roughness and residue burial were 4.99 cm and 33.57 %, respectively, with a desirability coefficient of 0.87. Precise adjustment of speed and plowing depth parameters for chisel plows is considered essential for achieving sustainable soil management and maximizing rainwater utilization. (c) 2025 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).