Design and development of a front mounted on-the-go soil strength profile sensor

Abstract

Soil compaction is a great problem since it affects crop growth and yield. The causes of soil compaction are the management practices in agricultural production. A common practice is to implement subsoiling at a few centimeters below the hardpan. Management practices, field traffic, and variations of the soil’s physical and chemical properties throughout the field cause variations in the soil compaction degree and depth. Subsoiling at certain depths can cause excessive energy consumption at a high cost. Therefore, agricultural tillage equipment could be improved by varying the tillage depth. Soil strength is the main indicator that depends on several soil properties such as bulk density, moisture, and organic soil texture content for determining the compaction level. The goal of this study was to develop an on-the-go sensor. It measured soil strength at multiple depths in order to determine the depth of the compacted soil layers. The mechanical frame of the sensor (body) was designed using Solidworks 3D CAD Design Software. Depth measurements were based on the Programmable Logic Controller (PLC) system. The data-gathering algorithm was developed with Phoenix Contact PC WORX software. It recorded the data flowing from the load cells, calculated the depth of the hardpan, and altered the depth of the chisel. In order to calibrate the load cell and compensate for differences among the load cells, static tests were conducted in a laboratory. The consistency of the sensing tips in terms of the input load – output load harmony was in linear format with higher R2 values ranging between 0.98 and 0.99. Consequently, the on-the-go soil sensor was developed for variable depth subsoiling. Dynamic tests revealed that the sensor was capable of monitoring the soil strength through the profile in order to determine the compaction level and hardpan depth. Moreover, the sensor was capable of adopting itself to crop varieties that have different critical compaction levels for root penetration.