Programa de Pós-Graduação em Agronomia

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Navegando Programa de Pós-Graduação em Agronomia por Assunto "3. Saúde e bem-estar"

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    Dissertação
    Atividade nematicida de extratos de Brugmansia suaveolens sobre Meloidogyne incognita
    (Universidade Estadual do Norte do Paraná, 2026) Venâncio, Stéphany de Campos; Alves, Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Alves, Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Poletto, Rodrigo de Souza; https://orcid.org/0000-0002-7034-7865; http://lattes.cnpq.br/8774064317309922; Silva, Santino Aleandro da; https://orcid.org/0000-0002-1019-1926; http://lattes.cnpq.br/8341476195396585
    Meloidogyne incognita stands out as one of the most aggressive and widely distributed species in tropical regions, causing severe damage to plant root systems. The need for alternatives to synthetic nematicides drives research into plant-based compounds with biological potential and lower environmental impact. In this context, the present study aimed to evaluate the nematicidal activity of aqueous and hydroalcoholic extracts from leaves and flowers of Brugmansia suaveolens (Solanaceae) on second-stage juveniles (J2) of M. incognita. The experiments were conducted under controlled laboratory conditions, using J2 obtained from infected tomato roots, processed with sodium hypochlorite solution and filtered through 250 and 500 mesh sieves. The suspensions containing J2 were exposed to two types of extracts (aqueous and hydroalcoholic) at different concentrations, and a negative control was performed with distilled water. The mortality of the juveniles was evaluated after 24 hours of exposure, and the data obtained were submitted to analysis of variance and Tukey's test (p<0.05). The aqueous extracts caused higher mortality of M. incognita J2, with the flower extract causing up to 98% mortality in all concentrations evaluated and showing no significant difference. The aqueous leaf extract, on the other hand, showed dose-dependent mortality, with values varying according to the dose tested. For the hydroalcoholic extracts, mortality was observed in the extracts obtained from flowers and leaves, with values ranging from 46 to 59% mortality. Analysis by gas chromatography coupled with mass spectrometry (GC-MS) for the detection and identification of volatile chemical constituents present in B. suaveolens extracts confirmed significant differences between the extracts, both in terms of the extraction method and the part of the plant used.
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    Dissertação
    Hidróxidos e carbonatos na dinâmica do pH do solo: efeitos na microbiota e no desenvolvimento da cultura da soja
    (Universidade Estadual do Norte do Paraná, 2026) Silva, Matheus Hashimoto da; Silva, Marcos Augusto Alves da; https://orcid.org/0000-0002-5570-8677; http://lattes.cnpq.br/4973981237909142; Nicolosi, Mateus Marrafon; http://lattes.cnpq.br/5740779198324583; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449; Dário, Gustavo; https://orcid.org/0000-0002-4648-6881; http://lattes.cnpq.br/5682942731827088; Alves, Karina Aline; https://orcid.org/0000-0002-8916-0224; http://lattes.cnpq.br/6915234182529881
    In agriculture, soil amendments play a crucial role in supplying nutrients, correcting pH, and promoting a range of vital benefits for healthy plant development. In this context, this study aimed to evaluate the efficiency of pH correction at different soil depths in soybean cultivation, considering the application of amendments composed of calcium and magnesium hydroxides and carbonates, in order to determine the most suitable parameters for the use of these elements. The treatments were organized in a randomized complete block design (RCBD) with four replications, using plots of 2.7 m wide by 5 m long, totaling an area of 13.5 m² per plot. The trial included a total of 14 treatments, organized as follows: control (T1); applications of hydroxides and carbonates, in granular and powder form, at doses corresponding to 50, 100, and 150% of the recommended dose, all associated with the biological mixture (T2 to T13); and a treatment composed only of the biological mixture (T14). The biological mixture was composed of Bacillus amyloliquefaciens, Bacillus subtilis, Bacillus aryabhattai, Trichoderma sp., Bradyrhizobium japonicum, and Azospirillum brasiliense, which were mixed and applied to the soil 31 days after crop emergence. The following variables were considered for evaluation: pH correction in the 0-10, 0-20, and 20-40 cm soil depth layers; changes in calcium, magnesium, and phosphorus levels; root system dry mass (RSM); shoot dry mass (SDM); number of pods per plant (NPP); thousand-grain weight (TGW); final crop yield (bags ha⁻¹); and monitoring of soil microbiological activities. The application of hydroxides resulted in a greater increase in soil pH in both evaluated depth layers compared to the application of carbonates. Forty-five days after the application of the amendments, it was observed that, in the 0–10 cm layer and at the highest dose used (1,428 kg ha⁻¹), the hydroxides raised the soil pH from 4.7 to 5.4, while carbonate, at the same dose, increased it to 4.9. The correction of the soil pH promoted a more favorable environment for the microbiota, increasing biological activity and nutrient availability. The improvement of the chemical and biological components of the soil resulted in greater root development and an increase in the number of pods per plant, culminating in increased soybean crop productivity.