TEDE Coleção: Doutorado em Agronomia

Indicadores de qualidade do solo em sistemas de produção agrícola em solos arenosos

Tue, 31 Mar 2026 00:00:00 GMT

Título: Indicadores de qualidade do solo em sistemas de produção agrícola em solos arenosos Autor: Cunha, Marcello Augusto dias da Primeiro orientador: Moro, Edemar Abstract: In tropical sandy soils of Western São Paulo State, soil quality responds strongly to land use and the degree of soil disturbance. This study compared five soil management systems: Pasture, Pasture-ILP, Crop-ILP, Pivot irrigation, and Forest, aiming to identify sensitive sustainability indicators. The approach integrated chemical fractions of soil organic matter (SOM) with microbiological and enzymatic indicators. The objective was to discriminate among management systems and support monitoring and decision-making. The study was conducted at Fazenda Ybyeté Porã, in Rancharia, São Paulo State, Brazil, on sandy soils, predominantly Ultisols and Oxisols, from May 2022 to May 2023. SOM was assessed by chemical fractionation into fulvic acid (FA), humic acid (HA), and humin (HU), in addition to biological indicators: soil respiration, microbial biomass carbon (MBC), qCO2, and enzymatic activities (FDA, dehydrogenase, β-glucosidase, arylsulfatase, and phosphatase). Management systems and soil depths (0–10 and 10–20 cm) were compared using ANOVA and integrated multivariate analyses of the attributes. In the conclusions, in 2022 FA (labile fraction) was the most sensitive chemical attribute, ranging from 0,87 to 4,30 g kg−1, with the highest values under Pasture (4,30) and Pivot irrigation (3,89). HA (more stable fraction) was higher under less disturbed systems, particularly Pasture (1,75 g kg−1) and Forest (1,15 g kg−1), and lowest under Pasture-ILP (0,55 g kg−1). HU (most recalcitrant fraction and an indicator of long-term carbon sequestration) highlighted better performance of systems with lower soil disturbance: in 2022, Pasture showed the highest HU at 0–10 cm (8,04 g kg−1) and maintained vertical stability in 2023 (5,69 g kg−1 at the surface and 5,62 g kg−1 at depth); in contrast, Crop-ILP exhibited reduced stabilization, dropping to 2,73 g kg−1 at 10–20 cm, suggesting an effect of soil disturbance. Biological indicators reinforced this pattern: in 2022, soil respiration was highest under Pasture (0,12 mg CO2 hora−1) and lowest under Crop-ILP (0,026 mg CO2 hora−1). In 2023, MBC was highest under Pasture (181,76 mg C g−1 soil), followed by Forest (172,93 mg C g−1), whereas the lowest values occurred under Pivot irrigation (87,47 mg C g−1) and Crop-ILP (84,56 mg C g−1). In 2022, arylsulfatase activity was consistently highest under Pasture (230,8 µg PNP g−1 soil h−1), while Pivot irrigation showed the lowest activity (43 µg PNP g−1 soil h−1). Overall, a positive association was observed between conservation-oriented management (reduced soil disturbance), higher carbon contents in humified fractions, and greater biological activity. Pasture emerged as the best treatment for promoting soil quality, while Pasture-ILP and Crop-ILP were intermediate and promising alternatives for sandy soils in Western São Paulo State. The combined use of SOM chemical fractionation (FA, HA, and HU) with enzymatic and microbial indicators provides a robust toolkit for monitoring and decision support in production systems. Instituição: Universidade do Oeste Paulista Tipo do documento: Tese

Manejo da adubação fosfatada em cana-de-açúcar: efeitos de fontes de fertilizantes fosfatados na dinâmica do fosfóro em solo arenoso

Mon, 09 Sep 2024 00:00:00 GMT

Título: Manejo da adubação fosfatada em cana-de-açúcar: efeitos de fontes de fertilizantes fosfatados na dinâmica do fosfóro em solo arenoso Autor: Cassimiro, Juliana Bonfim Primeiro orientador: Tiritan, Carlos Sérgio Abstract: Brazil is the largest producer of sugarcane (Saccharum spp. L.; Poaceae), with approximately 8.2 million hectares cultivated in the 2022/2023 season, generating an estimated production of 625 million tons. This crop plays a crucial role in the economy, not only in sugar production but also in the generation of renewable energy and animal feed. In this context, efficient phosphorus (P) management in the soil becomes essential, since most Brazilian soils are naturally low in this nutrient. The experiment was conducted in a commercial area of a sugar-energy mill located in Monte Castelo, São Paulo State, Brazil, during two consecutive growing seasons (2020/21 and 2021/22). Two phosphorus sources were evaluated: conventional monoammonium phosphate (MAP) and polymer-coated monoammonium phosphate, applied at different rates and management strategies. Soil phosphorus availability was determined using the Ion Exchange Resin and Mehlich-1 extraction methods at different depths of the soil profile, in addition to evaluating the plant nutritional status and productive attributes. Chapter I presents the results related to soil phosphorus availability and the nutritional response of the crop as affected by phosphate fertilizer sources and rates. Chapter II discusses phosphorus lability in soil cultivated with sugarcane through the fractionation of different forms of the nutrient in the soil. The results show that the interaction between fertilizer sources, rates, and application methods significantly influences phosphorus dynamics in the soil, highlighting the potential of coated fertilizers to reduce adsorption reactions and increase nutrient use efficiency. Therefore, proper management of phosphorus fertilization is a key strategy to optimize phosphorus availability, promote greater agronomic efficiency, and contribute to more sustainable production systems in sugarcane cultivation. Instituição: Universidade do Oeste Paulista Tipo do documento: Tese

Atenuaçãodo estresse por calor em cultivares de algodoeiro pela aplicação de bioestimulante

Mon, 14 Apr 2025 00:00:00 GMT

Título: Atenuaçãodo estresse por calor em cultivares de algodoeiro pela aplicação de bioestimulante Autor: Arruda, Rúbia Nascimento Crivelli Primeiro orientador: Echer, Fábio Rafael Abstract: Cotton (Gossypium hirsutum L.) is essential for the textile industry, as well as for producing vegetable oil and animal feed. Brazil stands out as one of the leading producers, especially in tropical and subtropical regions, facing challenges due to adverse climatic variations. This study evaluated the productivity and fiber quality of different cotton cultivars treated with a biostimulant, aiming to mitigate thermal stress under high-temperature conditions in Mato Grosso. The experiment was conducted in a completely randomized design, with a subdivided scheme, comprising 12 treatments (combinations of cultivars and application of the biostimulant Megafol®) and four replicates, in the municipalities of Sorriso, Tabaporã, and Porto dos Gaúchos. The bio-stimulant was applied starting at the B1 stage (first floral bud appearance) at a dose of 250 mL/ha, with reapplications every 15 days, totaling six applications and an accumulated volume of 1.5 L/ha. Harvest evaluations included productive parameters and fiber quality attributes. The results indicated that genetic (cultivars) and environmental (cultivation sites) factors significantly influenced fiber productivity and quality. The cultivars DP 1949B3RF and FM 974GLT stood out in yield and fiber strength. Climatic conditions, especially temperature, directly affected cotton quality and performance, highlighting the need for adaptive strategies to mitigate thermal stress effects. It was concluded that there is a difference among cultivars regarding the yield and quality of cotton fiber in regions with high temperatures. The biostimulant showed a punctual and variable effect, with more consistent gains in Porto dos Gaúchos, especially in boll retention and seed formation, but it was not determinant for yield or fiber quality. Instituição: Universidade do Oeste Paulista Tipo do documento: Dissertação

Tratamento de sementes com o micronutriente níquel em plântulas de genótipos de soja

Wed, 30 Apr 2025 00:00:00 GMT

Título: Tratamento de sementes com o micronutriente níquel em plântulas de genótipos de soja Autor: Ferreira, Tainara Romani Primeiro orientador: Putti, Jéssica Pigatto Barcelos Abstract: Nutritional management practices are essential to ensure the sustainability of agriculture in tropical agroecosystems. In the soybean cultivation system, modern genotypes are becoming more productive and more demanding in terms of nutrients, thus, there is concern regarding the current fertilizer recommendation to attend the nutritional plants demand. In this scenario, the application of emerging nutrients, such as nickel (Ni), can play a key role. This micronutrient is a cofactor of the enzymes urease and hydrogenase, which act in the nitrogen (N) metabolism in plants, in addition to acting in seed germination. However, studies on methods of application for this micronutrient, especially seed treatment, are incipient. The research project aims to evaluate the response of seedlings of modern soybean genotypes to fertilization with micronutrient Ni supplied in seed treatment. Furthermore, the project aims to determine the agronomic dose of this micronutrient, as well as evaluate the symptoms of its phytotoxicity. In the laboratory, six doses of Ni will be tested on six modern genotypes cultivated in tropical conditions. For this purpose, the experiment was implemented on germination paper and conducted in an incubator under controlled conditions. After seven days of implantation, the height of the aerial part and length of the root system were evaluated. The experimental design was completely randomized, with four replicates. The results were analyzed by analysis of variance and, when significant were analyzed by regression test, and the means were compared by the Tukey test (p < 0.05).Cultivars respond differently to Ni doses. For responsive cultivars, Ni application via seed treatment was beneficial up to a Ni dose of 66 mg kg-1 of seeds. Ni doses greater than 66 mg kg-1 of seeds increased the percentages of seedlings abnormal and dead seeds, and reduced the root and shoot lengths of seedlings. Instituição: Universidade do Oeste Paulista Tipo do documento: Dissertação