A Review of Soil Sensors for Precision Agriculture

Abstract

Ever since the dawn of human civilization, agriculture has driven scientific, engineering, and technological developments. Today, it is technology’s turn to drive agriculture because of the increasing population of the world and accompanying challenges in food production that include reducing cultivable land, compromised soil health, ever-increasing stressors on crops, detrimental climatic changes, scarcity of water and energy, etc. Technologies developed for human health, wellbeing, and comfort are now being utilized for improving agriculture, and justifiably so. Just as precision medicine is being developed for humans, it is being adapted for precision agriculture. Central to this critical endeavour are the soil sensors. To complement many insightful reviews that are available on this topic, this review article takes a comprehensive view by focusing on only three important soil sensors, namely, pH, nutrients, and moisture. In order to provide a complete view of the topic, this paper begins with a glimpse of the ever-growing list of research publications and proceeds to give an overview of transduction principles, multiple ways of measuring the aforesaid three soil parameters, capabilities and limitations of existing sensor techniques, status of commercially available sensors, integration of sensors into state-of-the-art precision and digital agricultural practices, and finally future perspectives.