Optical Sensing Methods for Assessment of Soil Macronutrients and other Properties for Application in Precision Agriculture:A review

Abstract

With the advancement in science and technology, a lot of attention has been focused worldwide in the agricultural sector. With the ever increasing population, the demand for crop cultivation has raised enormously which in turn has lead to increased use of fertilizers to meet the demands. However, over application of fertilizers besides hampering the quality of crops, also leads to ecological imbalance by polluting water bodies as well as ground water due to chemical run off. So with the increasing awareness of fertilizers effects on environment and quality of soil as well as crops, issues like precision agriculture and site specific management has come to the forefront of present day technological development in agriculture and ecology. Nitrogen, phosphorous and potassium are three main macronutrients required for plant growth and are also the main constituents of fertilizer. So, researchers worldwide are trying to develop ways for on-the-go in-situ sensing and assessment of soil properties, so as to optimize the amount of fertilizers to be used while increasing the productivity without causing damage to the environment. In this review, efforts have been made to review the optical sensing technologies adopted by various researchers in last 15 years and thereafter identify the gaps and challenges and recommendations for required attention and work in this field.

Keywords: Precision Agriculture, Nitrogen, Phosphorous, Potassium, Fertilizer, Near Infrared Reflectance Spectroscopy (NIRS), Raman Spectroscopy, Attenuated Total Reflectance Spectroscopy.