FCT - Artigos publicados em periodicos

URI Permanente para esta coleçãohttp://200.137.215.59//handle/ri/11335

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Claras intrusion a slab break-off model for mafic–ultramafic igneous rocks in the south Brasília Belt: insights related to post-collisional magmatism
(2025) Carvalho, D. R. D.; Aguiar, I. M.; Temporim, Filipe Altoé; Melo, Rodrigo Prudente de; Yokoyama, Elder
The extensional phase of orogens records the evolution of the lithospheric mantle along convergent plate boundaries, spanning from pre- to post-collisional stages. Post-collisional mafic-ultramafic magmatism may represent the ascent of asthenospheric magmas during orogenic collapse and the contribution of metasomatized lithospheric sources in the final stages of orogenesis. The Águas Claras intrusion (AC), situated within the Arenópolis Magmatic Arc in the southern segment of the Brasília Belt (BB), constitutes part of a suite of Ediacaran post-collisional mafic-ultramafic intrusions. We present a detailed analysis of the AC intrusive body based on geological and the integration of new and available geochemical data. The lithotypes of the AC are petrographically identified as peridotites, pyroxenites, and norites. The samples are part of the tholeiitic series, with Mg enrichment. The magma that generated the analyzed rocks has heterogeneous mantle sources. The AC rocks have a mantle source related to the asthenosphere with little interaction with the lithospheric mantle. Through the results of this work the adiabatic decompression melting of the asthenosphere necessary for magmatism may have been triggered by some major tectonic disturbance of the subducted plate. Therefore, a slab break-off model is proposed for BB. This is in agreement with a review of BB that suggested a model in which in the period between approximately 660 and 620 Ma the evolution of the Arenópolis Arc was the result of alternating extension events associated with short episodes of plate tilting. These findings provide significant insights into the post-collisional tectonic evolution of the BB, supporting a slab break-off model as the principal mechanism for the generation of mafic-ultramafic magmatism during late Ediacaran times.
Unraveling remagnetization sources using statistical learning
(2025) Gallo, Leandro Cesar; Domeier, Mathew Michael; Antonio, Paul Yves Jean; Sapienza, Facundo; Rapalini, Augusto Ernesto; Font, Eric Claude; Adatte, Thierry; Trindade, Ricardo Ivan Ferreira; Temporim, Filipe Altoé; Tonti-Filippin, Justin A. D.
The paleomagnetic archive provides invaluable insights into Earth’s history, but its records are often obscured by various geological processes. A prime example is remagnetization, which can replace the original natural remanent magnetization. Although magnetic overprints can be detected by traditional paleomagnetic tests, the mechanisms responsible for them often remain elusive because linking bulk magnetic properties to their microscopic sources is inherently challenging. Here, we bridge this gap by pairing an extensive rock magnetic and geochemical dataset with statistical learning techniques for the first time. Using a Random Forest regressor trained on geochemical data, we accurately predict the growth of fine-grained magnetite in an undeformed late Ediacaran section of remagnetized carbonate rocks from Paraguay. Our modeling results identify the K/Al ratio -alongside K and Sr contents—as key predictors of this remagnetization mechanism. Notably, clay mineralogy analyses further link the K/Al ratio to enhanced clay authigenesis (illitization) driven by K-feldspar dissolution and albitization—processes that also release iron. Together, these findings indicate that remagnetization occurred via authigenic magnetite formation under isochemical diagenesis—without the involvement of external fluids. This novel application of statistical learning to uncover the geochemical drivers of chemical remagnetizations provides a robust framework to investigate and understand these events. It could also open new avenues for their direct dating, thereby significantly enriching the global paleomagnetic record.
Análise mineralógica e aplicaçõestecnológicas do resíduo da extração de esmeraldas dos Garimpos de Carnaíba e Socotó/BA em composição de massas cerâmicas
(2025) Gentil, Talita Fernanda Carvalho; Nogueira Neto, José de Araújo; Mattos, Irani Clezar; Machado, Tércio Graciano; Lima, Martha Noélia; Guimarães, Vinícius Ferraz
The extraction of emeralds in the Carnaíba and Campo Formoso mountain ranges in Bahia generates significant environmental residue. This study aimed to characterize the residue from the Carnaíba (Pindobaçu-BA) and Socotó (Campo Formoso-BA) mines and to develop composite materials with clay for the production of ceramic materials in the construction industry. Formulations were prepared with varying concentrations of clay and mineral residue (10%, 20%, 30%, 40%, and 50%), which were subjected to chemical and mineralogical analyses using X-ray fluorescence and diffraction. The samples were sintered at different temperatures (850°C, 900°C, 950°C, 1000°C, 1100°C, and 1200°C) and tested for water absorption (WA%), apparent porosity (AP%), linear shrinkage (LS%), loss on ignition (LOI%) and flexural strength (FS MPa). The results revealed important characteristics for the ceramic industry, such as the presence of SiO2and Al2O3, which positively affect the properties of the final pieces. The mineralogical diversity, including mullite, metakaolinite, indialite, and quartz, contributed to the strength and stability of the composites. The formulations C20(20% Carnaíba residue) and S10(10% Socotó residue) achieved the best results, standing out for their technical feasibility and sustainability in ceramic production.
Decoding the structural architecture of the northern copper belt (Carajás Province) and Bacajá domain using airborne geophysics (Brazil)
(2026) Dutra, Luiz Fernandes; Melo, Gustavo Henrique Coelho de; Ribeiro, Brener Otávio Luiz; Temporim, Filipe Altoé
Copper is a critical metal for the global energy transition. Yet, declining discovery rates and increasing demand necessitate more efficient mineral exploration strategies grounded in a mineral systems approach. The Carajás Province (Amazonian Craton, Brazil) is one of the world’s premier copper-producing regions, hosting several iron oxide–copper– gold (IOCG) and related deposits. The Northern Copper Belt (NCB), located near the boundary between the Carajás and Bacajá domains, records a multiphase deformational and metallogenetic evolution from the Neoarchaean to Paleoproterozoic. Despite extensive previous studies, uncertainties remain regarding the geometry, depth, and continuity of the regional structures that control copper mineralization, as well as the nature of the tectonic boundary between the Carajás and Bacajá domains. As a result, through an integration of airborne magnetic, gravity, gamma-ray spectrometry, morpholineament, and spatial analyses, we characterized the tectono-structural framework of the NCB and the southern Bacajá Domain. This will provide new constraints on the geodynamic evolution of this world-class copper metallogenic belt, elucidating crustal-scale structures and patterns of hydrothermal alteration and fluid pathways, and enhancing understanding of the potential for further discoveries.
Levantamentos dos registros de Mesosauridae depositados nas instituições do estado de Goiás: espécimes e salvaguarda
(2026) Candeiro, Carlos Roberto dos Anjos; Vieira, Lucas Santos; Rodrigues, João Eduardo Campelo; Canile, Fernanda Maciel; Paulo, Pedro Oliveira
Mesosaurs were possibly one of the first amniotes adapted to aquatic life, with their fossils being found in both Southern South America and South Africa, and which were important for studies of Continental Drift. In Brazil, they occur mainly in the Irati Formation, with emphasis on the state of Goiás. The municipalities of Montividiu, Perolândia and Jataí concentrate the majority of fossil finds. The methodological steps used in this work include: (1) bibliographic surveys; (2) study of areas of interest; (3) technical visits to institutions; (4) cataloging of materials housed in institutions; (5) preparation of a location map with the origin of Mesosauridae fossils in the state of Goiás. The study aims to catalog and map fossils in institutions in Goiás, creating a database and a map of possible occurrence locations, contributing to the knowledge about mesosaurids.
Emplacement mechanisms of the Córrego Seco post-collisional mafic pluton revealed by AMS and gravity data, Brasília orogenic belt
(2026) Temporim, Filipe Altoé; Costa, G. S.; Souza Junior, Gelson Ferreira de; Melo, Rodrigo Prudente de; Barros, L. M.; Rodrigues, Sergio Wilians de Oliveira; Fontoura, João Antônio Silva; Trindade, Ricardo Ivan Ferreira
The Corrego ́ Seco (CS) pluton, located in the southern Brasília Orogenic Belt (BOB), central Brazil, represents a key expression of post-collisional mafic magmatism emplaced during the late Ediacaran (~630–610 Ma). The intrusion exhibits inverse zoning, with a gabbroic core surrounded by dioritic margins, and abundant mingling and hybridization textures that point to incremental construction by multiple magma pulses. To constrain its emplacement mechanisms, we integrate anisotropy of magnetic susceptibility (AMS), anisotropy of anhysteretic remanent magnetization (AARM), petrographic analyses, and gravity data. AMS and AARM fabrics reveal a concentric magnetic foliation pattern around the gabbroic core within a westward-dipping tabular pluton, reflecting magma flow and late-stage solid-state overprints. Petrographic observations highlight localized crystal- supported deformation along pluton margins and in adjacent country rocks, consistent with reduced melt frac- tions during final crystallization. Gravity modeling based on 73 new stations and 3D inversion demonstrates a westward-dipping geometry with thickened roots toward the west. These structural and geophysical features indicate that pluton emplacement was controlled by crustal-scale discontinuities and shear zones, with the asymmetric westward-dipping geometry being inconsistent with simple diapiric ballooning models. Integration of magnetic, petrographic, and gravimetric evidence supports a model of stepwise pluton assembly, where magma ascent was strongly controlled by inherited suture at the boundary between the Arenopolis ́ Arc and the Anapolis ́ –Itauçu Complex. This interpretation provides a key tectonic constraint, indicating that magmatism postdated the main suturing processes during the terminal stages of Gondwana amalgamation.
Paleodirections and paleointensity of the Zimbros dikes (South Brazil): evidence for ultralow fields and hints of a dipole in the mid-Ediacaran
(2026) Tomé, Camila Rocha; Savian, Jairo Francisco; Oliveira, Wellington Paulo de; Hartmann, Gelvam André; Fontoura, João Antônio Silva; Domeier, Mathew Michael; Temporim, Filipe Altoé; Hinrichs, Ruth; Trindade, Ricardo Ivan Ferreira; Bitencourt, Maria de Fátima Aparecida Saraiva
Ediacaran (635–538 Ma) paleomagnetic records from multiple continents are associated with populations of paleopoles nearly synchronous in time but widely separated in space. Some hypotheses to explain these data appeal to rapid motions of the solid Earth, whereas others invoke a non-geocentric axial dipole (GAD) or an extremely weak GAD field with high paleosecular variation and frequent reversals. We present new directional and absolute paleointensity constraints obtained from two mafic dikes of the Zimbros Intrusive Suite (ca. 590 Ma) in the Dom Feliciano Belt (DFB), southern Brazil. Magnetite and low-Ti titanomagnetite are the main magnetic carriers, associated with pseudo-single-domain to multidomain magnetic behavior. Directional ana- lyses reveal that the dikes host two distinct magnetization components. The low-temperature component is attributed to pyrrhotite, likely related to late-stage tectonic events. The high-temperature component, held by low-Ti titanomagnetite/magnetite, is interpreted as the characteristic remanent magnetization. This compo- nent’s directions are antipodal and compatible with a dominantly GAD field, but a high degree of directional dispersion may reflect an unstable field. Absolute paleointensity experiments yielded 19 reliable estimates with virtual dipole moments (VDM) of 0.38 ± 0.15 × 1022 and 0.89 ± 0.33 × 1022 Am2. The validity of these ultra-low estimates was confirmed by their stability under progressively stricter selection criteria based on curvature analysis, indicating the estimates' internal consistency. The obtained VDMs are consistent with coeval results from Laurentia and Baltica, and with an existing time-averaged field estimate from the DFB. Together, these results provide additional evidence of a remarkably weak Ediacaran geomagnetic field.
Stratigraphy, vertebrate fauna and environments of the upper cretaceous of the northwestern Bauru group, Brazil with south american paleobiogeographical implications
(2026) Candeiro, Carlos Roberto dos Anjos; Brusatte, Fernanda Maciel Canile; Brusatte, Stephen ; Dias, Airton Natanael Coelho; González Riga, Bernardo Javier; Oliveira, Emerson Ferreira de; Paulo, Pedro Oliveira; Rodrigues , Sergio Wilians de Oliveira; Ferreira, Bruno Martins; Queiroz, Glayce Kelly de
The Adamantina and Marília formations are the only units of the Upper Cretaceous Bauru Group exposed in the southern region of the state of Goiás, Central Brazil. They are made up of sandy siltstones and very fine gray sandstones. These units record the lacustrine sedimentation that prevailed in the first stages of Bauru Group evolution. Based on surface data, a regional stratigraphic analysis was carried out to establish the faunistic composition and paleogeographical distribution of the depositional environment that acted in the final phase of the geological unit sedimentation. Given the scarcity and little knowledge of the Cretaceous terrestrial fauna of the north of the Bauru Group, this portion of the southern state of Goiás in Brazil holds great promise for providing new paleontological data. This will contribute to increasing knowledge and refining biogeographic hypotheses of the vertebrate fauna that help to explain the distribu-tions of numerous clades in post-Campanian South America.
Tectonometamorphic evolution of the Anicuns-Itaberaí sequence, southern Brasília Orogen: evidence of deep burial and syn-collisional exhumation
(2026) Vieira, Otávio Passo; Melo, Rodrigo Prudente de; Fumes, Regiane Andrade; Brod, Gabriel Silveira; Temporim, Filipe Altoé; Rodrigues, Sérgio Willians de Oliveira; Luvizotto, George Luiz
Metamorphic pressure–temperature (P–T) conditions in the Southern Brasília Orogen are relatively well con- strained, particularly in its southernmost segments. However, the central and northern portions need further attention, especially regarding the metamorphism affecting the volcano-sedimentary sequences of the Arenopolis ́ Magmatic Arc (AMA). The Anicuns–Itaberaí Sequence (AIS), located in the southern segment of the AMA, comprises a well-exposed metavolcano-sedimentary succession of mafic to ultramafic metavolcanic rocks, met- achert, metarhythmite, marble lenses and quartzite. Well-preserved outcrops in the lowlands surrounding the Serra da Jiboia region, located in the central portion of the study area, were used to investigate the structural features and deformation recorded in metasedimentary rocks of the AIS and two samples of metagreywackes were selected for metamorphic modelling. The analyzed rocks correspond to garnet–chlorite–biotite–muscovite schists and were selected for microstructural analysis, quantitative mineral mapping, and thermodynamic modelling based on electron microprobe analyses. The results indicate that the peak metamorphic assemblage (garnet + biotite + plagioclase + muscovite + rutile + ilmenite) was stable at temperatures above 600 ◦C and pressures exceeding 0.95 GPa. The metamorphic evolution, inferred from compositional zoning in garnet, defines a clockwise P–T path, with initial garnet growth at 525–555 ◦C and 0.67–0.77 GPa, a metamorphic peak at 660 ◦C and 1.16–1.30 GPa, followed by decompression between 550 and 585 ◦C and 0.65–0.79 GPa. These results indicate that the AIS schists reached high-pressure amphibolite-facies conditions, exceeding those typical of the Barrovian metamorphism, and point to a collisional tectonic regime characterized by deep crustal burial and subsequent exhumation. Deformation structures were chronologically classified into four distinct phases (D1 to D4). The main deformation event (D2) is characterized by asymmetric folding, while subsequent reverse faulting and shearing (D3) are associated with post-burial exhumation during syn-collisional processes. Micro- structural evidence suggests that the metamorphic peak likely occurred between the end of D1 and the onset of D2, indicating that peak mineral growth was broadly synchronous with early stages of the main deformation phase and burial.
Nano x-ray tomography at the CARNAÚBA Beamline (SIRIUS-LNLS) in diamond mineral inclusions
(2025) Camarda, Carolina Michelon; Silva, Francisco Mateus Cirilo da; Piccino Neto, Antonio Carlos; Ferraz, Paola Cunha; Oliveira, João Fernando Gomes de; Gervasoni, Fernanda; Jalowitzk, Tiago Luis Reis; Miqueles, Eduardo Xavier; Tolentino, Hélio Cesar Nogueira
Iron oxyhydroxide as water carrier to the Earth’s mantle
(2026) Camarda, Carolina Michelon; Gervasoni, Fernanda; Jalowitzk, Tiago Luis Reis; Silva, Francisco Mateus Cirilo da; Piccino Neto, Antonio Carlos; Ferraz, Paola Cunha; Oliveira, João Fernando Gomes de; Miqueles, Eduardo Xavier; Archilha, Nathaly Lopes; Torquato, Igor Ferreira
The discovery of new mineral phases capable of transporting water into the Earth’s mantle via subduction zones is essential for understanding the deep Earth water cycle and its influence on mantle dynamics. Recent experimental and computational studies have proposed that certain hydrated oxyhydroxides may remain stable under deep mantle conditions, particularly within cold subducting slabs. Here, we report an advanced synchrotron multi-technique study on a natural complex iron oxyhydroxide mineral preserved within a Juína diamond, which may offer new evidence on water transport via cold subducted slabs and highlights the potential role of iron oxyhydroxides as carriers of volatiles into Earth’s interior.
Grahampearsonite, Ca2P2O7, a new mineral found in a super-deep diamond from Juína, Brazil
(2025) Wang, Yanjuan; Nestola, Fabrizio; Day, Maxwell C.; Jalowitzk, Tiago Luis Reis; Rodrigues, Eduardo Novais; Gervasoni, Fernanda; Cedeño, Daniel Grings; Silva, Sebastião William da; Fuck, Reinhardt Adolfo; Nava, Jacopo Giovanni
Grahampearsonite, ideally Ca2P2O7, is a new mineral (IMA 2025-017) that was found in a multiphase inclusion in a super-deep diamond (sample RV43) from the Chapadão plateau, Mato Grosso, Brazil. The new mineral is closely associated with tuite and with other mineral inclusions in the host diamond (that are not in direct contact with grahampearsonite) including larnite, merrillite, apatite, diopside, ilmenite, magnetite, calcite, and an unidentified phosphate phase. X-ray diffraction analyses, performed directly on the inclusion while still entrapped in the diamond, revealed a tetragonal crystal structure (space group P41), with unit-cell parameters a = 6.6966(16) Å, c = 24.145(11) Å, and V = 1082.8(6) Å3 . The identification of grahampearsonite as the natural analog of synthetic β-Ca2P2O7 is strongly supported by micro-Raman, FTIR, crystal chemical, and X-ray diffraction data. The occurrence of grahampearsonite and tuite in a super-deep diamond indicates that grahampearsonite could be related to the decomposition of tuite and may provide new insights into the Earth’s deep phosphorus reservoir and the crust-mantle phosphorus cycle. The new mineral honors Graham D. Pearson, University of Alberta, for his outstanding contributions to diamond research.
Synchrotron- and laboratory-based micro-CT for the analysis of inclusions in diamonds: a comparative approach
(2026) Kazmirczak, Catharina Caixeta; Carmelo, Adriana Chatack; Jalowitzk, Tiago Luis Reis; Bernardes, Renato Borges; Gervasoni, Fernanda; Camarda, Carolina Michelon; Salvador, Aluizio José; Cedeño, Daniel Grings; Archilha, Nathaly Lopes
This study evaluates the effectiveness of laboratory-based micro-CT for analyzing inclusions in diamonds and compares it to synchrotron-based systems. Synchrotron-based micro-CT provides top-tier X-ray imaging due to its high brilliance, collimated and quasi-monochromatic radiation, which enables superior resolution, contrast, and minimal artifacts. However, limited accessibility restricts its widespread use, especially in preliminary or exploratory studies that require prompt beamtime access. In comparison, laboratory-based micro-CT offers a more accessible alternative. In this study, synchrotron data were acquired at the MOGNO beamline of Sirius, the Brazilian Synchrotron Light Laboratory, part of the Brazilian Center for Research in Energy and Materials, whereas lab-based scans were performed using a Bruker SkyScan 1172 micro-CT. Laboratory-based scans at 80 kV, with a 0.5-mm-thick aluminum filter, and exposure times of 1250–2100 ms significantly improved contrast and segmentation, reducing artifacts such as beam hardening and grayscale overlap. In contrast, settings of 59 kV, no filter, and 430–750 ms exposures introduced noise and spurious inclusions. Both techniques mapped the spatial distribution of inclusions in a 6-mm-long diamond, capturing the detailed morphology and internal attenuation contrast of a 156-μm-long inclusion. Our findings indicate that, with properly selected acquisition parameters, laboratory-based micro-CT can generate high-quality 3D visualizations of diamond inclusions, making it a viable alternative when synchrotron beamtime is unavailable. The technique's 3D visualization capability has vast applications in geosciences, materials science, and forensics, particularly in guiding further analytical techniques. Future research should focus on refining acquisition configurations to improve image quality and on improving software used to generate 3D models.
Inovações na fertilização do solo e o papel dos remineralizadores
(2025) Santos, Luiz Fernando dos; Abrantes, Ewerton Gonçalves de; Marchi, Giuliano; Martins, Éder de Souza
Objective – To review the role of soil remineralizers (REM) in tropical soil fertility, focusing on CEC, organic carbon, and environmental mitigation potential. Methodology – Literature review using scientific databases (Web of Science and Google Scholar), selecting studies on REM, CEC, and carbon dynamics. Originality/relevance – The study addresses gaps in understanding charge generation and carbon stability in tropical soils amended with REM, highlighting its relevance for sustainable agriculture. Results – REM increase CEC, improve nutrient availability, and contribute to carbon stabilization in soils. Theoretical/methodological contributions – Advances in the understanding of bioweathering and mineral–organic matter interactions in soils. Social and environmental contributions – Reduction in dependence on chemical inputs, promotion of rock-based agriculture, and mitigation of environmental impacts.
Zoneamento agrogeológico do Chapadão Urucuia e seu entorno
(2025) Araujo, Leonardo de Matos; Braga, Flávia Cristina Silveira; Martins, Éder de Souza
Brazil’s dependence on imported fertilizers is a strategic challenge, with 86.1% of agricultural inputs sourced from foreign markets. This vulnerability particularly affects the country’s main agricultural frontiers, such as the western region of Bahia, where the Urucuia Plateau is located. This study focused on the prospecting and evaluation of rocks with potential for use as soil remineralizers (rock powders), emphasizing the identification of regional sources of potassium, phosphorus, calcium, and magnesium. Considering the gradual nutrient release typical of these inputs, the research included the development of thematic maps that indicate both the spatial distribution of agrominerals and their degree of reactivity. The methodology integrated chemical, physical, and mineralogical analyses, along with geoprocessing techniques applied to the agrogeological zoning of the Urucuia Plateau and its surroundings. The main highlights were the biotite-schist from the Rio Preto Group, in Formosa do Rio Preto (BA), containing 6.32% K2O, 7.71% MgO, and 4.21% CaO; and the carbonatite from the Angico dos Dias Metacarbonatitic Complex, in Campo Alegre de Lourdes (BA), with 10.8% P2O5 and 12.9% CaO. The analyzed materials presented potassium, phosphorus, calcium, and magnesium levels consistent with the criteria established by the Brazilian Ministry of Agriculture for remineralizer certification, in addition to low concentrations of potentially toxic elements, ensuring environmental safety and agricultural viability. Beyond promoting sustainable plant nutrition, these regional sources represent a strategic alternative to reduce dependency on external inputs and mitigate risks associated with international fertilizer market crises, strengthening agricultural security in western Bahia.
Soil carbon and nitrogen in silicate agromineral-managed pasture: a seven-year study in the Cerrado
(2025) Silva, Priscila Brelaz da; Carvalho, Arminda Moreira de; Junqueira, Ana Maria Resende; Soares, João Paulo Guimarães; Sá, Marcos Aurelio Carolino de; Martins, Giuliano Marchi Éder de Souza; Figueiredo, Cícero Célio de; Santos, Luiz Fernando dos; Sousa, Thais Rodrigues de; Oliveira, Alexsandra Duarte de
The objective of this work was to investigate the long-term effect of the silicate agrominerals ‒ basalt, biotite schist, and kamafugite ‒, as well as of potassium chloride fertilizer on soil carbon (C) and nitrogen (N) contents in pasture systems cultivated with Urochloa brizantha 'BRS Paiaguás', in the Brazilian Cerrado biome. The evaluated parameters were soil C and N stocks, organic matter fractions, and chemical and physical attributes. No significant differences were observed across treatments for C and N stocks. The total organic carbon (TOC) content of kamafugite and basalt was 15.56 g kg- ¹ and 8.21 g kg-1, respectively, which were not significant. TOC correlated positively with the biological soil quality index and nutrient cycling. The particulate organic carbon fraction contributed to carbon retention near the surface, accounting for approximately 50% of C, due to biomass input and microbial activity. Micronutrient levels varied among treatments, and kamafugite showed the highest concentrations. Soil correction and fertilization applied across all treatments, before the application of silicate agrominerals, limited the isolation of agromineral effects. The study underscores the need of undertaking extended research on silicate agrominerals in chronosequences, particularly regarding nutrient dynamics and C stabilization in tropical soils.
Produção de fertilizante orgânico por meio da compostagem tropical conjunta de resíduos orgânicos com pó de rocha
(2025) Höfig, Pedro; Martins, Éder de Souza; Giasson, Élvio; Martins, Amanda Posselt
The search for profitable and permanent agriculture involves valuing the sources of nutrients available regionally, which provides more autonomy for the rural sector in relation to fertilization. The joint composting of organic waste and ground rocks combines two ancestral techniques, but it is not very widespread. The objective of this study was to evaluate a fertilizer produced by the joint composting of organic waste and rock dust. The components used to produce the compost were cattle manure, corn silage, coffee husks, agricultural gypsum and phonolite rock dust. The temperature and humidity of the compost were measured daily. The aeration was carried out with the Jaguar JC 4000 composter and the humidification was carried out with a 20-thousand-liter towable water tank. The chemical, organic, biological, and sanitary analyses indicated that the composting process was carried out correctly. Thus, the compost produced with regional sources of nutrients has good quality and can be used in agriculture, since it meets the necessary requirements to be classified as class A organic compound fertilizer, but it was noted that part of the nutrients in the rock dust was not made available by composting, due to its mineralogy and granulometry.
Potential of granitoid rock powder to enhance soil fertility and crop nutrition
(2026) Fernandes, Sidiney Moreira; Castoldi, Gustavo; Selleri, Caroline de Figueiredo Oliveira; Silva, Gutierres Nelson; Moreira, Wagner Henrique; Marcante, Nericlenes Chaves; Mandro, Mathaus Antonio Elias; Martins, Éder de Souza; Santos, Elcio Ferreira
The use of granitoid rock as a soil remineralizer has gained attention for its potential to enhance soil fertility and improve crop nutrition in agriculture. This study evaluates the impact of granitoid rock on the chemical properties of Typic Quartzipsamment soil and the growth and nutrient uptake of maize (Zea mays) and common bean (Phaseolus vulgaris) plants. Granitoid powder from four different origins was applied at rates of 0, 10, 20, 30, and 40 t ha−1 in a controlled greenhouse experiment, which lasted 65days after plant emergence (until flowering stage). Results showed a linear increase in soil concentrations of phosphorus, potassium, calcium, and magnesium with increasing granitoid rock powder rates, leading to higher base saturation levels. In maize and bean plants, granitoid rock powder application significantly increased shoot dry mass (g plant−1), plant height (cm), and stem diameter (mm). Nutrient uptake, calculated as the total content of macro- and micronutrients in the shoot (mg plant−1), also increased, particularly at the highest rate (40 t ha−1). These results demonstrate the effect of granitoid rock powder on a sandy, quartz-rich, nutrient-poor soil, which likely enhanced the positive plant responses. The findings indicate that granitoid rock powder can be an effective and sustainable nutrient source, gradually releasing nutrients and contributing to agricultural productivity and environmental conservation. However, further studies in different soil types and under field conditions are necessary to confirm its agronomic potential on a broader scale.
Agrochemicals and biological inputs in soybean farms in Brazil: cases of substitutive, incremental, and alternative uses
(2026) Medina, Gabriel da Silva; Silveira, Fernando Augusto da; Freitas, Elis Marina de; Resende, Vitor Hugo Souza; Martins, Éder de Souza
Farmers worldwide use agrochemicals and biological inputs to fertilize fields, manage pests and diseases, and promote plant growth. However, there is still limited field-based evidence on the extent to which biological inputs function as substitutes, incremental complements, or alternatives to agrochemicals in key farming practices. This study presents preliminary results on the use of synthetic and biological inputs for the most common practices employed by large soybean farmers in central Brazil. We combined literature review, regulatory data on registered biological products, and in-person interviews with farmers and market experts. Our results show that, in most practices, biological products are adopted alongside the continued use of synthetic inputs, in some cases reducing the frequency or dosage of chemical applications. Inoculants based on nitrogen-fixing bacteria already substitute mineral nitrogen fertilization in soybean, while biosolubilizers and plant activators are used incrementally to enhance the efficiency of chemical fertilizers. Bioinsecticides and biofungicides are predominantly employed as alternatives within spray programs, especially in preventive or early interventions, thereby reducing the number of conventional pesticide sprays. Bionematicides emerge as the main biological tools used as substitutes for synthetic nematicides in preventive treatments, whereas biological herbicides are not yet available on the market. Field evidence presented in this study showed that farmers adopt biological products in diverse ways, including as substitutes, incremental, or alternatives to chemical products, depending on the technologies available. These findings provide a more nuanced understanding than the common views that, on one hand, biological inputs simply complement rather than substitute chemical products, and on the other, that biological solutions can fully substitute synthetic products. As environmental and economic implications, we conclude that biological inputs can underpin trajectories towards more regenerative management in large-scale soybean systems, even when synthetic inputs remain part of the production matrix.
Silicate agrominerals mitigate greenhouse gas emissions and enhance soil carbon in tropical pasture of the Brazilian Cerrado
(2026) Santos, Marcos Vinícius Araujo dos; Oliveira, Alexsandra Duarte de; Figueiredo, Cícero Célio de; Soares, João Paulo Guimarães; Marchi, Giuliano; Santana, Thayna Xavier; Andrade, Altair César Moreira de; Muniz, Daphne Heloísa de Freitas; Lustosa Filho, José Ferreira; Carvalho, Arminda Moreira de; Sá, Marcos Aurélio Carolino de; Martins, Éder de Souza
The mitigation of greenhouse gas emissions in livestock farming is one of the main chal- lenges for agriculture in the Cerrado biome. Among promising practices, the use of soil remineralizers (REM) stands out as a sustainable and complementary alternative to con- ventional fertilizers. This study evaluated the effects of applying REM derived from basalt and biotite schist on emissions of N2O, CO2 and CH4, the global warming potential (GWP), as well as on soil carbon and nitrogen in Urochloa brizantha cv. BRS Paiaguás pasture. The experiment was conducted in randomized blocks with five treatments (control, KCl, basalt8.33 Mg ha−1, basalt 40 Mg ha−1 , and biotite schist 151 Mg ha−1). Results indicated thatKCl and high-dose basalt (40 Mg ha−1) promoted greater accumulated N2O emissions and higher GWP values. In contrast, biotite schist reduced N2O emissions and showed the lowest GWP (81.67 kg CO2 eq. ha−1), while basalt at a moderate dose (8.33 Mg ha−1)increased soil C and N stocks. It is concluded that soil remineralizers, especially those derived from biotite schist, represent viable alternatives to reduce environmental impacts and promote the sustainability of tropical agricultural systems in Cerrado biome.

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