Using phytolith analysis to assist with soil classification: A report on the 16th Brazilian Meeting on Soil Classification and Correlation – Marcia R Calegari
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- November 14, 2025
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The LEDA Laboratory, led by Marcia Calegari, provides paleoecological information that contributes to understanding soil genesis and classification in the semi-arid Caatinga biome (Brazil).
BAHIA, BRAZIL – From October 26th to November 1st, 2025, the state of Bahia in northeastern Brazil hosted the 16th Brazilian Soil Classification and Correlation Meeting (XVI RCC). Under the theme “What does Bahia have?”, the technical field excursion covered 1,100 km within the Caatinga biome, visiting 16 soil profiles across diverse landscapes, including the São Francisco Valley, the Chapada Diamantina, the Irecê Plateau, and the Sertanejo Pediplain.
The event, promoted by the Brazilian Soil Science Society (SBCS) and organized by the Federal University of Recôncavo da Bahia (UFRB) and the Federal University of Viçosa’s Soil Department, in partnership with several other institutions in the state of Bahia (northeastern Brazil), allowed participants to deepen their knowledge about the origin, use, and classification of soils through an integrated analysis of soils and landscapes.
The Brazilian Soil Classification System (SiBCS) is based on morphological, physical, and chemical diagnostic attributes of soil profiles. However, some soil characteristics are dynamic and can be altered by management and pedogenic processes that can obscure information about the genesis and environmental history of a soil, making its classification difficult.
In this context, silica phytolith analysis stands out as a powerful paleoecological tool, providing complementary data that enrich morphogenetic interpretation and help refine soil classification. Phytoliths offer not just a snapshot of the soil’s current condition, but also an integrated narrative of its formation, connecting the soil to the environmental and historical processes that shaped it.
Notably, this was the third time that phytolith analysis was used in soil classification at the RCC, underscoring its growing recognition and value in Brazilian soil science.
Phytolith analyses for this event were conducted by the Multiuser Laboratory for Environmental Dynamics Studies (LEDA) at the State University of Western Paraná (UNIOESTE), under the coordination of Prof. Marcia R. Calegari.
The team used phytolith analysis and ¹⁴C dating to analyze four soil profiles with unique natures and properties to better understand soil genesis by accessing their biotic memories.
In the set of analyzed profiles, 21 basic morphotypes were identified, taxonomically grouped into 7 families, plus 8 morphotypes with high redundancy among Eudicot plants. This assemblage allowed researchers to identify vegetation structures and infer variations in environmental moisture, as well as evidence of material transport and the occurrence of fires.
“In semi-arid regions like the Brazilian Caatinga, phytoliths are sometimes the only proxy that persists in the soil, enabling the study of vegetation changes over time and facilitating paleoenvironmental studies,” highlighted the LEDA team.
This application demonstrates the potential of phytolith science to contribute significantly to pedological studies and offer a unique window into the past that helps scientists better classify and understand the complex and diverse soils of Brazil.
