A low-cost soil strength and subsoiling depth measuring system and soil mapping derived from field tests

Abstract

Since soil compaction is one of the most severe problems in plant production, this research had a goal of fabricating an automatic system to measure field soil strength in term of horizontal penetration resistance and subsoiling depth mounted on a working tractor to help manage sugarcane production more effectively. In this study, a low-cost system was designed to measure the involved factor values, and the components were sourced in the local market. The soil strength measuring device used a conical tip that penetrated the soil and obtained a signal by using a full Wheatstone bridge of strain gauges. The subsoiling depth measurement and the global positioning were achieved by using an ultrasonic module Baumer U500.DA0-11110575 Ultrasonic Sensor Block M12 and ublox C94-M8P-1 GPS module antenna, respectively. The data processing and recording system used an ESP32 board to control all the equipment and manage the related data. The results from the field test confirmed that the measuring system of the required values could be mounted on a working tractor and record the data. The soil strength map of the sugarcane field could represent variation of the soil property in term of horizontal penetration resistance spatially and tended to agree with those measured manually in three area parts: the frontal, middle and rear parts. The subsoiling depth map showed that most of plowing depths were 30–40 cm in the frontal and middle area parts, while it was 40–50 cm for the rear area part. The soil strength and subsoiling depth maps reflected the plowing work well, where the higher soil strength found the shallower depth.