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

Abstract

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.

Combining Laser-Induced Breakdown Spectroscopy (LIBS) and Visible Near-Infrared Spectroscopy (Vis-NIRS) for Soil Phosphorus Determination

“…It is well known that sample heterogeneity is a challenge for quantitative LIBS determinations, and that is particularly true for soils because of their diverse and intricate composition [ 34 ]. Even though LIBS is an elemental analysis technique, several studies have shown its ability to estimate soil pH [ 35 ], humification degree of soil organic matter (SOM) [ 36 ], and soil texture [ 37 , 38 ] through relationships between the studied properties and the soil chemical composition [ 39 ]. For P, only one study tried to estimate plant-available soil P fractions by the use of multivariate calibration methods, in which not only spectral P signals but also signals from other soil elements affected the model.…”

Applications of laser‐induced breakdown spectroscopy for soil characterization, part II: Review of elemental analysis and soil classification

“…As stated in Part I of this review (Villas-Boas et al, 2019) in this issue, LIBS holds great potential for soil chemical and physical characterization, not only for routine laboratory work but also for in-field analyses, especially with respect to applications in precision agriculture. In Part I, we also provided an introductory overview on how to use LIBS for soil analysis and presented recent LIBS applications in soil characterization, including soil pH, humification degree of soil organic matter (SOM) and soil texture.…”

“…Rapid determination of soil elemental composition is important for improving agricultural production and reducing agricultural environmental impacts. Among recent analytical techniques, laser-induced breakdown spectroscopy (LIBS) has become one of the most prominent, with great potential for real-time and large-scale soil analyses (Villas-Boas et al, 2019). Laser-induced breakdown spectroscopy has been successfully used to determine the content of soil carbon (C) (Cremers & Radziemski, 2013;Senesi & Senesi, 2016;Zorov, Popov, Zaytsev, & Labutin, 2015), macro-and micronutrients (Bublitz, Dölle, Schade, Hartmann, & Horn, 2001;Díaz, Hahn, & Molina, 2012;Harris, Cremers, Ebinger, & Bluhm, 2004;Popov, Labutin, & Zorov, 2009;Rühlmann, Büchele, Ostermann, Bald, & Schmid, 2018;Sallé, Cremers, Maurice, Wiens, & Fichet, 2005) and toxic elements (Bousquet, Sirven, & Canioni, 2007;Dell'Aglio et al, 2011;Hilbk-Kortenbruck, Noll, Wintjens, Falk, & Becker, 2001;Multari, Foster, Cremers, & Ferris, 1996;Senesi et al, 2009;Wang et al, 2018;Wisbrun, Schechter, Niessner, & Schroeder, 1993;Zaytsev, Krylov, Popov, Zorov, & Labutin, 2018).…”

Editorial for Soil chemical, physical and biological interfacial reactions (Commission 2.5, WCSS) special section

“…The two‐part paper by Villas‐Boas, Franco, Martin‐Neto, Gollany, and Milori (2020a,b) describes the principles and applications in soil science of laser‐induced breakdown spectroscopy (LIBS). These papers give a remarkable overview of this technique, which has the advantages of minimal sample preparation, and therefore avoidance of inherent creation of artefacts.…”

“…The results may be qualitative or quantitative depending on user experience and prior knowledge of the samples. The critical analysis of the first paper, Villas‐Boas et al (2020a), indicates how matrix effects can be minimized and background signal normalized to optimize the technique. With appropriate calibration, physical characterization can be made by applying multivariate methods to measured elemental composition.…”