Applications of laser-induced breakdown spectroscopy for soil analysis, part I: Review of fundamentals and chemical and physical properties

Laser-induced breakdown spectroscopy (LIBS) has become a prominent analytical technique in recent years for real-time characterization of soil properties. However, only a few studies of soil chemical and physical properties have been reported using LIBS until recently. The aims of this article are to: (a) provide the basic principles of LIBS for soil analysis and (b) present the use of LIBS for the analysis of soil pH, soil texture and the humification degree of soil organic matter (SOM). The second article will cover soil classification and soil elemental analysis, including plant nutrients, carbon (C) and toxic elements. LIBS is a multi-element analytical technique based on atomic spectroscopy that employs a high-energy laser pulse focused onto a sample surface to create a transient plasma. It is a spectroscopic analytical technique that requires very little or no sample preparation, examines each sample in seconds, and offers a flexible platform for the examination of a broad array of elements in the sample. LIBS also can be used to infer soil chemical and physical properties if a relationship exists between the chemical composition and the soil properties. With proper calibration, LIBS has a great potential for real-time in-field soil analysis and precision farming that could lead to improved soil management and agricultural production, and reduced agricultural environmental impacts. Highlights Laser-induced breakdown spectroscopy (LIBS) is a fast, multi-element analytical technique with great potential for soil characterization. Basic principles of LIBS and general description of its use for soil analysis are provided. Soil chemical and physical characterization by LIBS are reviewed and compared to other techniques. LIBS advantages, limitations and challenges are discussed for soil chemical and physical characterization.