CASTRO, T. B. de

COELHO, M. R.

FONTANA, A.

JUCÁ, N. M. C.

POPPIA, R. J.

SHIMIDT, G. B.

SOUZA, A. M. de

VALDERRAMA, P.

WINKLER, T. C. B.

Repository Open Access to Scientific Information from Embrapa

ANALYTICAL VALIDATION OF A MULTIVARIATE CALIBRATION METHOD FOR DETERMINATION OF SOIL ORGANIC CARBON BY NEAR INFRARED SPECTROSCOPYAndré M. de  Souzab,  Maurício R. Coelhob,  Ademir Fontanab,  Thayane C. Barbosa Winklerb, Natasha M. C. Jucáb, Thais B. de Castrob, Gabriela B. Shimidtb,  Patrícia Valderramac, Ronei Jesus Poppia. aInstitute of Chemistry, University of Campinas (UNICAMP), P.O. Box 6154, 13084-971 Campinas, SP, Brazil.bEmbrapa Soils, Brazilian Agricultural Research Corporation, Rua Jardim Botânico 1024, CEP 22460-000, Rio de Janeiro (RJ), Brazil. andremarcelo.souza@embrapa.br cUniversidade Tecnológica Federal do Paraná, Coordenação de Licenciatura em Química, BR 369, Km  0.5, CEP 87301-006 Campo Mourão, PR, BrazilThe near infrared diffuse reflectance spectroscopy (NIR - DRS , 700-2500 nm) or NIR - DRS associated with the visible region (Vis/NIR - DRS , 400-780 nm ) is considered the most promising analytical technique to replace current routine analysis of soil organic carbon (SOC) due to the numerous advantages of this technique over the traditional ones:  it  is  cheaper,  faster,  non-destructive  and  "clean".  However,  one  of  the  key challenges to enable the implementation of NIR-DRS spectroscopy as a routine method in  soil  laboratories  is  to  build  robust  multivariate  models  from  a  large  number  of samples, sufficiently representative of the soil types found in a certain region. In this work, local and global multivariate calibration models were developed and validated for the determination of SOC on a representative set of brasilian soil samples, as well as a critical view of a possible implementation of the NIR-DRS spectroscopy as a routine method of SOC in a near future in all laboratory of soil analysis in Brazil.The  spectral  data  were  preprocessed  by  Saviztky-Golay's  first  derivative  and  the variable selection was made by the variable importance for projection (VIP) method (Andersen and Bro,  2010).  The multivariate  models were built  with PLS regression (Wold et al., 2001) and the outliers detection were perfomed with a in-house Matlab program by the method described by Martens and Naes (1989).Martens, H. and Næs, T., Multivariate Calibration, John Wiley & Sons, New York, NY,1989.Andersen, C.M., Bro, R., 2010. Variable selection in regression-a tutorial. J. Chemom. 24, 728–737.Wold, S., Sjöström, M., Eriksson, L., 2001. PLS-regression: a basic tool of chemometrics. Chemom. Intell. Lab. Syst. 58, 109–130.

Analytical validation of a multivariate calibration method for determination of soil organic carbon by near infrared spectroscopy.

Analytical validation of a multivariate calibration method for determination of soil organic carbon by near infrared spectroscopy.

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