Simplifying Sample Preparation for Soil Fertility Analysis by X-ray Fluorescence Spectrometry

Author(s)

Tavares, Tiago Rodrigues ^[1] ; Nunes, Lidiane Cristina ^[2] ; Alves, Elton Eduardo Novais ^[3] ; de Almeida, Eduardo ^[4] ; Maldaner, Leonardo Felipe ^[1] ; Krug, Francisco Jose ^[2] ; de Carvalho, Hudson Wallace Pereira ^[4] ; Molin, Jose Paulo ^[1]

Affiliation

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr ESALQ, Dept Biosyst Engn, Lab Precis Agr LAP, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Sao Paulo, Ctr Nucl Energy Agr CENA, Lab Analyt Chem LQA, BR-13416000 Piracicaba, SP - Brazil

^[3] Univ Sao Paulo, Ctr Nucl Energy Agr CENA, Lab Carbon LC14 14, BR-13416000 Piracicaba, SP - Brazil

^[4] Univ Sao Paulo, Ctr Nucl Energy Agr CENA, Lab Nucl Instrumentat LIN, BR-13416000 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: SENSORS; v. 19, n. 23 DEC 2019.
• Web of Science Citations: 0

Abstract

Portable X-ray fluorescence (pXRF) sensors allow one to collect digital data in a practical and environmentally friendly way, as a complementary method to traditional laboratory analyses. This work aimed to assess the performance of a pXRF sensor to predict exchangeable nutrients in soil samples by using two contrasting strategies of sample preparation: pressed pellets and loose powder (<2 mm). Pellets were prepared using soil and a cellulose binder at 10% w w(-1) followed by grinding for 20 min. Sample homogeneity was probed by X-ray fluorescence microanalysis. Exchangeable nutrients were assessed by pXRF furnished with a Rh X-ray tube and silicon drift detector. The calibration models were obtained using 58 soil samples and leave-one-out cross-validation. The predictive capabilities of the models were appropriate for both exchangeable K (ex-K) and Ca (ex-Ca) determinations with R-2 >= 0.76 and RPIQ > 2.5. Although XRF analysis of pressed pellets allowed a slight gain in performance over loose powder samples for the prediction of ex-K and ex-Ca, satisfactory performances were also obtained with loose powders, which require minimal sample preparation. The prediction models with local samples showed promising results and encourage more detailed investigations for the application of pXRF in tropical soils. (AU)

• FAPESP's process: 18/08877-2 - CLIMATE AND ENVIRONMENTAL CHANGES IMPACTS ON BIOGEOCHEMISTRY OF BRAZILIAN MANGROVE ECOSYSTEM
• Grantee: Elton Eduardo Novais Alves
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/21969-0 - Evaluation of alternative techniques to traditional laboratory analysis for prediction of attributes in agricultural soils: approaches using VisNIR, XRF and LIBS spectroscopy
• Grantee: Tiago Rodrigues Tavares
• Support Opportunities: Scholarships in Brazil - Doctorate