Design, Calibration, and Experimental Study of Low-Cost Resistivity-Based Soil Moisture Sensor for Detecting Moisture at Different Depths of a Soil

Abstract

Soil moisture is one of the important abiotic factors for the proper growth of plant and scheduled irrigation in agriculture. Soil moisture stress would lead to the improper growth of crop and reduction in yield. Nowadays, most of the scheduled irrigation systems are depending on the compact soil moisture sensor to detect the soil moisture level and actuate the irrigation accordingly. Even though many soil moisture sensors are already available, the limitation of the existing soil moisture sensor poses further challenges for improvement in soil moisture sensor. In this work, one of the limitations of existing soil moisture sensor is unable to detect the soil moisture level at different granularities of soil considered and proposed an improvement. In the proposed work, the multiple parallel probes at different depths of soil are used to detect the soil moisture at different vertical profiles of soil using the basic soil properties of variation in soil resistivity due to soil moisture. The empirical study of proposed work showcases the behavioral characteristics of variation in soil resistivity due to moisture and relationship between change in soil resistivity of upper and lower probes and its possible use to detect the presence of soil moisture at different depths of soil.