Low-Cost, Compact Mobile Robot for Autonomous Soil Monitoring in Crop Fields

This paper presents the development and evaluation of a mobile robotic platform for autonomous crop field scouting and soil sensing. The system combines a durable commercial chassis kit with custom 3D-printed casings, enabling reliable operation across diverse outdoor field environments. The robot features encoder-controlled motors and a swivelmounted front frame, allowing versatile and agile navigation through narrow crop rows and uneven terrain, as demonstrated in field trials conducted in cotton and peanut fields. A soil sensing mechanism, driven by a 360° servo motor and employing a linear gear-and-rack mechanism, enables consistent soil penetration. Integrated with a low-cost 7 -in-1 soil sensor, the platform provides real-time mapping of key soil parame-ters-nitrogen, phosphorus, potassium, electrical conductivity, pH, temperature, and moisture-to support data-driven farm management decisions. Preliminary experiments evaluated the robot's field navigation and soil sensing performance. Results demonstrate the potential of the platform for low-cost, mobile soil sensing, while also highlighting limitations in the current sensor's accuracy.