Design an Electromagnetic Sensor to Measure the Organic Carbon in Soil and Its Validation With Standard Walkley-Black Method

Organic carbon is probably the most important organic matter, which affects soil properties and is a prime indicator of soil quality. In this letter, the electromagnetic sensor is designed with a combination of inductance and capacitance using an interdigital and spiral design, which has been fabricated on printed circuit boards to test the impedance of various soil samples to determine the percentage of soil organic carbon. To validate the proposed design of the electromagnetic sensor, first, the organic carbon is determined using the standard procedure of the Walkley-Black (WB) method. For the detection of carbon in the soil, the samples have been collected from different pastoral areas around North Sydney, Australia. Further, the impedance of the soil is measured using the proposed electromagnetic sensor and builds the relationship between the percentage of organic carbon and the measured impedance. The sensitivity of the electromagnetic sensor is obtained with an accuracy within +/- 5% error in the multiple times (1000 times) runs. The developed model is also validated with experimental data to predict the percentage of organic carbon. The proposed electromagnetic sensor has the potential to be used on the ground to detect the carbon in the soil by considering the impact of temperature, humidity, and water.