A comprehensive survey of nondestructive sensing technologies for the detection of corn seeds in a closed trench and measuring planting depth to augment the conventional method

Abstract Due to the importance of planting depth on yield potential, we need to measure planting depth to improve planting depth accuracy. A number of pressure-based active planter depth control systems are commercially available. These systems actively control downward pressure on the planter units based on a target pressure setting. The necessary target pressure can change significantly depending on spatial and temporal conditions. However, precision planters are not equipped with subsurface sensors that enable detection and quantification of corn seed depth. The primary objective of this review was to evaluate nondestructive sensing technologies that may be used for corn seed detection, thereby enabling determination of planting depth in a closed trench. The sensors were reviewed in terms of their suitability for the application, operational requirements, and sensor advantages and limitations for soil subsurface detection. Ground Penetrating Radar (GPR) was recommended as a viable candidate for corn seed depth sensing but there is no single technique that can be conclusively identified as the best technology. A limitation of the available systems is that they do not provide a way to close loop control planting depth. A possible solution could be using sensor-based closed loop controls in respect to the planting depth. These could significantly improve the accuracy of pressure-based active control systems, and significantly improve the potential yield and economic benefits of planter depth control systems.