Banca de DEFESA: AMANDA SALES ALVES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : AMANDA SALES ALVES
DATE: 17/07/2026
TIME: 08:30
LOCAL: VIDEOCONFERÊNCIA
TITLE:

Black Soils: genesis, characterization, and classification in different environments

KEY WORDS:

Pedogenesis; Soil Classification Systems; Tropical Climate; Mediterranean Region; Anthropogenic Activity.

PAGES: 164
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

Black Soils are defined by the International Network of Black Soils (INBS) of the FAO/ITPS as mineral soils characterized by a dark surface horizon, high organic carbon content, and high base saturation. Although they have traditionally been associated with temperate regions, recent studies have demonstrated their occurrence in a wide range of environments. In this context, the aim of this thesis was to characterize Black Soils in tropical, Mediterranean, and anthropogenic environments by evaluating their morphological, physical, and chemical properties, taxonomic classification, and their conformity with the FAO/INBS concept. In the first chapter, the surface horizons of 38 soil profiles distributed across different Brazilian biomes were evaluated. The surface horizons exhibited high natural fertility, with mean Ca+Mg contents of 36.1 cmolc kg-1, mean soil organic carbon content of 28.1 g kg⁻¹, and mean organic carbon stocks (0–10 cm) of 33.5 Mg ha-1. Most profiles met the criteria of Categories 1 and 2 established by the INBS, with predominance of Chernossolos in the Brazilian Soil Classification System (SiBCS), corresponding mainly to Phaeozems, Chernozems, and Kastanozems in the World Reference Base for Soil Resources (WRB). The results also indicated that the minimum surface horizon thickness criterion of 25 cm may limit the recognition of Black Soils in tropical environments. In the second chapter, a database containing approximately 3,500 soil profiles from Catalonia was analyzed, from which 121 profiles were selected based on the properties of their surface horizons. Soil organic carbon (SOC) contents in the surface horizons ranged from 12.8 to 92.8 g kg-1, while base saturation averaged 99%. Statistical analyses grouped the profiles into four clusters, reflecting the influence of parent material, climate, and relief. The Black Soils occurred predominantly in forest and natural areas and exhibited considerable taxonomic diversity within both the WRB and Soil Taxonomy classification systems. In the third chapter, soil profiles developed on shell mounds (sambaquis) in the state of Maranhão, Brazil, were investigated, with emphasis on phosphorus fraction dynamics, soil genesis, and classification. The surface horizons exhibited dark colors, thickness greater than 25 cm, the presence of shells, high phosphorus, organic carbon, and calcium contents, as well as high base saturation, meeting the FAO/INBS criteria for Black Soils. The Olsen method proved to be the most appropriate for determining available phosphorus in sambaqui soils. According to the WRB, the profiles were classified as Pretic Anthrosols and Pretic Calcaric Cambisols, whereas in the Brazilian Soil Classification System (SiBCS) they were classified as Cambissolos. Overall, this thesis demonstrates that Black Soils constitute a group of soils sharing common characteristics while exhibiting substantial diversity in their edaphic properties and taxonomic classifications, reflecting the different environments in which they occur. These findings reinforce the importance of the conservation and sustainable management of Black Soils, as well as the recognition of their role in climate change mitigation.

COMMITTEE MEMBERS:
Externo à Instituição - MARCELINO SILVA FARIAS FILHO - UFMA
Externa à Instituição - CAROLINE DELPUPO SOUZA - IFMG
Externo à Instituição - RICARDO BERGAMO SCHENATO - UFSM
Externo à Instituição - ADEMIR FONTANA - EMBRAPA
Presidente - 387335 - LUCIA HELENA CUNHA DOS ANJOS