Tropical Soil Toposequence Characterization via pXRF Spectrometry

Abstract

Variability of elemental composition in a toposequence of quartzite‐derived soils in a tropical environment was evaluated via portable x‐ray fluorescence (pXRF) spectrometry. The toposequence featured different degrees of weathering and variable soil formation processes. Specifically, this study aimed to: (i) use elemental composition obtained through pXRF as a tool to investigate the degrees of weathering–leaching and pedogenic processes; and (ii) correlate elemental data with physicochemical properties of soils. Four soil profiles (Lithic Ustorthent, Typic Ustorthent, Typic Dystrudept, and Xanthic Hapludox) were described and sampled. Laboratory analysis for soil physicochemical characterization and pXRF were performed. Soils featured high contents of SiO2 due to the predominance of quartz in the rock. However, pXRF analysis revealed that the soils showed a decrease in such content with depth. Potassium contents tended to be greater in the C horizons since they are less weathered and retained greater amounts of K‐bearing minerals, such as muscovite. Al, Fe, Ca, Ti, Cu, and Sr increased their contents with increasing clay content in soils, while Zr generally remained stable. Ba was leached out of soils during weathering. Both CaO and Sr were positively correlated with exchangeable contents of Ca2+ and Mg2+, base saturation, pH, and cation exchange capacity, while inversely correlated to Al3+ saturation. Fe, Al, Ti, Ca, K, Cu, Rb, and Zr accumulated in soil in comparison with the parent material. Variability of elemental contents in soils with differential degrees of weathering–leaching can be easily accessed with pXRF and such data correlate well with several soil physicochemical properties. Core Ideas Toposequence of quartzite‐derived soils variability assessed by pXRF. Soils presented varying weathering degrees, from Entisols to Oxisols. pXRF elemental data correlated well with soil physical and chemical properties. Soil mineralogy and pXRF data elucidated soils variability with weathering. Al, Fe, Ca, Ti, Cu, and Sr increased with increasing clay content.

Morfologi Dan Klasifikasi Tanah Pada Toposekuen Lereng Barat Gunung Kelud, Kediri, Jawa Timur

“…Tanah yang berkembang ini memiliki tekstur yang beragam, tergantung dari jenis dan ukuran tephra yang keluar saat erupsi (Sukarman dan Suparto, 2015). Tekstur tanah vulkan sebagian besar memiliki partikel pasir dengan tekstur pasir hingga lempung berpasir (Silva, 2019).…”

Foliar Elemental Analysis of Brazilian Crops via Portable X-ray Fluorescence Spectrometry

“…Based on pXRF spectra, prediction models of many soil properties (e.g., pH, texture, soil organic matter, macroand micronutrients) have been established [27][28][29][30][31]. Several pXRF soil studies have been successfully conducted in tropical environments [32,33].…”