Near-Infrared Spectroscopy Coupled with Chemometrics Tools: A Rapid and Non-Destructive Alternative on Soil Evaluation

ABSTRACT

Near-infrared (NIR) spectroscopy is a rapid, non-destructive and accurate technique for analyzing a wide variety of samples, thus, the growing interest of using this technique in soil science. The objective of this study was to evaluate the potential of NIR spectroscopy to predict organic carbon (OC), total nitrogen (TN), available phosphorus (P) and available potassium (K) in the soil. NIR spectra from 20 cm³ of soil samples were acquired on the range of 750 to 2500 nm in diffuse reflectance mode, resolution of 16 cm⁻¹ and 64 scans. Eight models of calibration/validation were constructed. Calibration and validation models showed that the predictive potential of NIR varied with the specific soil property (OC, TN, P and K) under evaluation and according to the methodology employed in the model construction (cross-validation or test set). Good prediction models were obtained for OC and TN content based on the statistical parameters. Test set methodology was able to predict soil OC, TN, P, and K better than cross-validation methodology.

KEYWORDS:

• Phosphorus
• potassium
• NIR
• organic carbon
• total nitrogen

Acknowledgments

We thanks the (1) Universidade Tecnológica Federal do Paraná (UTFPR), Pato Branco, Paraná, Brazil, for the support on chemical and spectroscopic analyzes, (2) Central de Análises of UTFPR (Pato Branco, Paraná, Brazil), for the support on NIR analyzes, (3) Universidade Federal do Paraná (Curitiba, Paraná, Brazil) for the soil samples and Universidade Estadual de Londrina (Londrina, Paraná, Brazil) for the soil samples. This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Brazil (Process: 484934/2011-2).

Additional information

Notes on contributors

Jéssica Bassetto Carra

Jéssica Bassetto Carra has graduation at Industrial Chemistry (2016) and high school (2012) by Universidade Tecnológica Federal do Paraná.

Marciéli Fabris

Marciéli Fabris has graduation at Industrial Chemistry (2016) by Universidade Tecnológica Federal do Paraná.

Jeferson Dieckow

Jeferson Dieckow is Agronomist by Federal University of Santa Maria (1997). Master (2000) and Doctorate (2003) degrees in Soil Science by Universidade Federal do Rio Grande do Sul.

Osmar Rodrigues Brito

Osmar Rodrigues Brito is Agronomist by Universidade Federal de Viçosa (1979). Master degree in Plant Science (Plant Production) by Universidade Federal de Viçosa (1983) and Ph.D. in Agronomy (Plant Production) by Universidade Estadual Paulista Júlio de Mesquita Filho (1999).

Pedro Rodolfo Siqueira Vendrame

Pedro Rodolfo Siqueira Vendrame is Agronomist by Universidade Estadual de Londrina (2002), master's in Agronomy from Universidade Estadual de Londrina (2005) and Ph.D. in Agronomy from Universidade Estadual de Londrina (2008).

Larissa Macedo Dos Santos Tonial

Larissa Macedo dos Santos Tonial has a degree in Chemistry by Universidade Estadual de Ponta Grossa (2003), master in Science by Universidade de São Paulo-Instituto de Química de São Carlos (2006), Ph.D. in Analytical Chemistry by Universidade Federal de São Carlos (2010).