Crop rotations with corn and soybeans, along with biochar-based fertilization, were studied in China to see how they affect crop yield and quality traits. The study found that rotating corn and soybeans increased crop yield compared to growing them alone. The corn yield was higher in a corn-soybean-corn rotation, and soybean yield was higher in a soybean-corn-corn rotation. However, rotating crops had a negative effect on soybean protein content but a positive effect on oil content. Biochar-based fertilization did not affect crop yield but improved protein and oil content. Crop rotations also influenced soil nitrogen and potassium levels. Overall, crop rotations and biochar-based fertilization can enhance crop yield and quality in the long term, providing valuable insights for sustainable cropping systems.