A biochar production system includes a reactor body, a central rod disposed within the reactor body, a leveling arm extending from the central rod and configured to rotate about the central rod, and a bed level sensor system. The bed level sensor system includes a float configured to move from a resting position on a biomass in the reactor to an ending position upon contact with the leveling arm, and a level sensor coupled to the float via a connector. The level sensor is configured to correspondingly move with the float. A controller is configured to detect bed levels of the biomass within the reactor body, and determine a plurality of sample readings based on the detected bed levels.