Rapid, Nondestructive Total Elemental Analysis of Vertisol Soils using Portable X-ray Fluorescence

Portable X-ray fluorescence (PXRF) spectrometry can provide rapid and nondestructive analyses of agriculturally important elements in soil. To assess the applicability of PXRF for total element analysis of Vertisols, 20 soils were collected across northern New South Wales (NSW), Australia. Comparison of PXRF results were made with conventional standard microwave aqua regia (AR) digestion followed by inductively couple plasma optical emission spectroscopy (ICP-OES) analysis, laboratory X-ray fluorescence (LXRF), and neutron activation analysis (NAA). Strong linear correlations were found for As, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, Si, Ti, and Zn. We demonstrate that nondestructive analyses for total soil element determination, particularly Ca, Fe, Mn, and P, should now allow rapid elucidation of important chemical processes in Vertisols that are commonly only available following rigorous sample preparation and digestion. The integrated and robust character of PXRF instrumentation, requiring minimal or no dedicated laboratory infrastructure, is readily adaptable to a wide range of analytical situations.