Electrical Conductivity Sensing for Precision Agriculture: A Review (original) (raw)

2018, Harmony Search and Nature Inspired Optimization Algorithms

The main objective of precision agriculture (site-specific agriculture) is to maximize crop production profitability, improves product quality as well as protection of environment. The major drawback of site-specific agriculture is its inability to measure soil characteristics rapidly and inexpensively. Various manufacturers and researchers developed on the go soil sensors for measuring physiochemical and mechanical properties of soil. These sensors are based on electrical and electromagnetic, mechanical, acoustic, electrochemical and pneumatic techniques. Electric and electromagnetic sensors are widely used because of their rapid response, low cost and high durability. Electrical resistivity (ER), electromagnetic induction (EM) and time domain reflectrometery (TDR) are the techniques used for measuring soil electrical conductivity (EC). Electrical conductivity of soil has become widely used measurement for characterizing field variability in application to precision agriculture. Aqueous extract of soil sample is used to determine EC of soil sample but because of labor, time and cost of obtaining EC of soil sample from soil solution extracts, EC is shifted to EC of bulk soil and is known as apparent soil electrical conductivity (EC a). EC a is affected by physiochemical properties which include: clay content, soluble salts, soil moisture content, bulk density, soil organic matter, soil temperature, etc. EC a is a quick, reliable and simple method for measuring soil characteristics. The objective of this paper is to provide a review of the development and deployment of sensors applied for EC a measurement for agricultural purpose, working principle of soil EC a measurement, techniques and equipments used for measurement.