Sejam bem-vindos ao Poraquê, o Repositório Institucional (RI) da Universidade Federal do Oeste do Pará (Ufopa). Nosso objetivo é armazenar, preservar, dar acesso e visibilidade à produção científica em formato digital da universidade. O nome Poraquê é uma alusão ao peixe-elétrico da Amazônia, em que seu corpo é capaz de produzir pulsos elétricos, é dito, que enxergar no escuro, logo, possui autonomia energética, capaz de acender uma lâmpada

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    Selênio na Mitigação dos Efeitos da Restrição Hídrica em Sementes de Soja (Glycine max L.)
    (Universidade Federal do Oeste do Pará, 2026-06-17) BRITO, Ederlon Pinheiro; SILVA, Vanessa Beatriz Souza da; CRUZ, Flávio José Rodrigues; https://orcid.org/0000-0001-6701-8748; http://lattes.cnpq.br/0255249624668229; http://lattes.cnpq.br/0378457269228276; http://lattes.cnpq.br/6749859491419570; SANTOS, Raudielle Ferreira dos; https://orcid.org/0000-0003-0801-7491; http://lattes.cnpq.br/4820595976291360; ARÉVALO, Michelly Rios; http://lattes.cnpq.br/9084234962228553
    Seed priming with beneficial substances is a promising strategy to improve the germination performance of agricultural crops under adverse conditions. This study evaluated the effect of different concentrations of sodium selenite (0; 2.5; 5; 10; 20 and 40 mg/L) on the germination process and early seedling growth of soybean cultivar Lenda IPRO, subjected to water restriction simulated by polyethylene glycol 6000 (PEG 6000) at osmotic potentials of 0 and - 0.1 MPa. The experiment was conducted in a laboratory under a completely randomized design in a factorial scheme. Germination percentage, germination speed index, mean germination time, fresh and dry biomass accumulation, shoot and root length, and seedling vigor indexes were evaluated. Results indicated that low selenium concentrations, especially 5 mg/L, promoted seedling growth and vigor, even surpassing the control treatment in some variables under stress conditions. In contrast, the concentration of 40 mg/L showed a reduction, impairing germination and early development. Simulated water deficit mainly affected seed vigor without significantly compromising germination viability. It is concluded that seed priming with 5 mg/L of selenium represents an efficient alternative to mitigate the negative effects of water deficit during the early development stage of soybean.
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    Uso de Selênio no Condicionamento de Sementes de Soja: Germinação e Crescimento de Plântulas
    (Universidade Federal do Oeste do Pará, 2026-06-17) SANTOS, Deise de Souza; SOUZA, Márcia Lima de; CRUZ, Flávio José Rodrigues; https://orcid.org/0000-0001-6701-8748; http://lattes.cnpq.br/0255249624668229; http://lattes.cnpq.br/0596633935420029; SANTOS, Raudielle Ferreira dos; https://orcid.org/0000-0003-0801-7491; http://lattes.cnpq.br/4820595976291360; ARÉVALO, Michelly Rios; http://lattes.cnpq.br/9084234962228553
    The use of biostimulant substances in seed treatment has emerged as a promising strategy to improve the physiological performance of agricultural crops. In this context, the present study aimed to evaluate the effect of different selenium concentrations on the germination, vigor, and initial growth of soybean (Glycine max L.) seedlings of the Lenda IPRO cultivar through seed priming with sodium selenite (Na₂SeO₃). The experiment was conducted in a completely randomized design consisting of eight selenium concentrations (0, 2.5, 5, 10, 20, 40, 80, and 120 mg L⁻¹), with four replicates of 40 seeds each. Germination, biometric, and biomass parameters were evaluated, including germination percentage, germination speed index, mean germination time, shoot and root length, fresh and dry mass, and seedling vigor indices. The results demonstrated that sodium selenite significantly influenced germination, vigor, and the initial development of soybean seedlings. Low and intermediate concentrations showed performance similar to that of the control treatment for most of the evaluated variables and, in some characteristics, promoted seedling growth, indicating their potential to maintain or improve seed physiological quality when applied at appropriate doses. In contrast, higher concentrations, particularly 80 and 120 mg L⁻¹, significantly reduced germination, vigor, and seedling growth, demonstrating the phytotoxic effect of selenium. It can be concluded that the use of sodium selenite in soybean seed priming has the potential to enhance physiological performance and the initial establishment of the crop when applied at low concentrations. However, careful dose selection is essential, as high concentrations significantly impair the initial development of soybean seedlings.
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    Sindicato dos trabalhadores rurais agricultores e agricultoras familiares de Santarém: 50 anos de luta e representatividade no campo
    (Universidade Federal do Oeste do Pará, 2025-07-30) MESQUITA, Matheus Santos de; PESSÔA, Elen Cristina da Silva; http://lattes.cnpq.br/4877695895603188; http://lattes.cnpq.br/1931657517386363; REIS, Ana Beatriz Oliveira; https://orcid.org/0000-0002-0429-3125; http://lattes.cnpq.br/8425524082989615; COSTA, Márcia Janete da Cunha; http://lattes.cnpq.br/1733123463018004
    This undergraduate thesis comprehends the trajectory of the Rural Workers’ Union of Santarém (STTR), in the state of Pará, over its fifty years of existence, highlighting its role in defending family farming and the struggle for social rights in the Amazon countryside. The study contextualizes the union’s foundation in 1971 during Brazil’s military regime, and its transition from an assistance-based structure to an autonomous and combative organization aligned with the principles of the new unionism. Based on qualitative research, including bibliographic review, document analysis, and semi- structured interviews with union leaders, the study reveals how STTR has faced historical challenges such as land grabbing, state repression, agribusiness expansion, and peasant marginalization. The results demonstrate that the union played a key role in the creation of settlements, extractive reserves, and public policies directed at family farming. The interviews highlight the union’s ability to adapt to political and economic changes by incorporating digital tools, expanding alliances, and promoting new leadership training. Despite institutional setbacks and growing pressures from capital on rural territories, the STTR remains an essential organization in the defense of land, agroecology, and dignity in rural areas. The study concludes that its history reflects not only a struggle for rights but also the active resistance of Amazonian rural communities in the face of structural inequalities and contemporary threats.
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    Avaliação do rendimento de farinha no processamento de diferentes cultivares de mandioca (Manihot esculenta crantz) em áreas com e sem irrigação na região Oeste do Pará
    (Universidade Federal do Oeste do Pará, 2026-06-08) SARAIVA, Carla Andréa Figueira Roberto; PEREIRA, Idenilza Batista; VIEIRA, Jonathan Correa; http://lattes.cnpq.br/0625146331814138; VIEIRA, Dayse Drielly de Souza Santana; http://lattes.cnpq.br/2057759102444626; http://lattes.cnpq.br/5648831064329573; ALBA, Henry Daniel Ruiz; http://lattes.cnpq.br/9761256969956620; LAGES, Regina Pereira; https://orcid.org/0000-0002-2834-3182; http://lattes.cnpq.br/7180342393015907
    This study aimed to evaluate flour yield during the processing of different cassava cultivars in irrigated and non-irrigated areas in the western region of Pará. The experiment was conducted in Juruti, Pará, at the Farinharia Puxirum facility, using a completely randomized design (CRD) with a split-plot arrangement. Four cultivars were tested three improved by Embrapa and one landrace cultivar: i) BRS 420, ii) BRS Mari, iii) BRS Dourada (table cassava), and iv) Coaraci. Among the sixteen variables analyzed, key metrics included flour productivity, processing yield (an indicator of root starch content), starch content (SC), and flour yield. Processing was carried out in a semi-mechanized flour mill following standardized procedures, and data were analyzed using descriptive statistics to compare cultivars and management systems. Results indicated that irrigation positively influenced starch accumulation, reducing the amount of root required to produce 1 kg of flour from 5.10 kg to 3.70 kg for the Coaraci cultivar and from 9.40 kg to 7.43 kg for BRS Mari thereby increasing average values compared to non-irrigated areas and resulting in higher flour yields. Among the cultivars evaluated, Coaraci stood out as the most efficient in terms of flour yield under the irrigated regime, showing the best processing ratio (3.7 kg of unpeeled root per 1 kg of flour). BRS 420 also performed similarly, confirming its potential for flour production in the region. BRS Mari showed a positive response to irrigation but yielded lower results compared to the aforementioned cultivars. Finally, BRS Dourada showed equivalent yields but performed poorly in both areas analyzed. In this context, adopting irrigation is an effective strategy for increasing cassava profitability, directly impacting flour yield the primary derivative product in the western region of Pará. Furthermore, selecting the appropriate cultivar is crucial for production success, given that improved varieties from Embrapa offer opportunities for crop diversification and perform well in the region, while the 'Coaraci' landrace cultivar has proven highly competitive in terms of conversion efficiency, underscoring its importance for traditional and family-based farming systems.
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    Avaliação do crescimento e produtividade de uma cultivar de mandioca biofortificada em áreas com e sem irrigação no Baixo Amazonas
    (Universidade Federal do Oeste do Pará, 2026-06-03) PIMENTEL, David Mayke da Silva; SILVA, Isabela Ribeiro da; VIEIRA, Dayse Drielly Souza Santana; http://lattes.cnpq.br/2057759102444626; ROSSI, Celeste Queiroz; http://lattes.cnpq.br/4242217997345355; http://lattes.cnpq.br/4955453999793665; http://lattes.cnpq.br/3020946674722471; CRUZ, Flávio José Rodrigues; https://orcid.org/0000-0001-6701-8748; http://lattes.cnpq.br/0255249624668229; ARÉVALO, Michelly Rios; http://lattes.cnpq.br/9084234962228553
    Cassava is one of the main agricultural crops in the Amazon region, playing an important socioeconomic role in family farming and regional food security. In this context, biofortified cultivars such as BRS Dourada show potential for nutritional improvement and adaptation to tropical edaphoclimatic conditions. This study aimed to evaluate the growth and productivity of the BRS Dourada cassava cultivar under irrigated and non-irrigated conditions in the municipality of Juruti, Pará, Brazil. The experiment was conducted at the Farinharia Puxirum property, located in the Lago Verde community, from February 2025 to February 2026. A completely randomized design was adopted, consisting of two treatments, T1 with irrigation and T2 without irrigation, with 14 replications each. Irrigation was performed using a microsprinkler system during the Amazonian dry season, considering the physical and hydraulic characteristics of the soil, classified as sandy and with low water retention capacity. Evaluations were carried out at 90, 180, 270, and 360 days after planting, analyzing vegetative and productive variables, including total number of leaves, plant height, stem diameter, number of roots, root length and diameter, productivity, and harvest index. Data were subjected to analysis of variance, and means were compared using Student’s t-test at a 5% significance level. The results demonstrated satisfactory agronomic performance of the cultivar under the environmental conditions of the Lower Amazon region, showing good adaptation to the cultivation environment. Irrigation did not promote significant differences for most of the analyzed variables, indicating productive stability of the cultivar even under moderate water restriction conditions. Therefore, the BRS Dourada cultivar shows potential for regional cultivation and may contribute to strengthening cassava production and food security in the Amazon.