https://repositorio.ufu.br/handle/123456789/18942 2026-10-04T00:56:36Z 2026-10-04T00:56:36Z https://repositorio.ufu.br/handle/123456789/50486 2026-09-30T06:20:56Z 2026-07-30T00:00:00Z

Title: Acumulação de arsênio em Coffea arabica sob diferentes fontes via solo Abstract: Arsenic (As) is a toxic metalloid widely distributed in Brazilian agricultural soils, whose presence, even at low concentrations, represents a significant risk to human health due to its high mobility and potential for accumulation in plants. This risk may be intensified by anthropogenic activities, such as the use of contaminated fertilizers, including ulexite, which may contain high concentrations of this element. In this context, the present study aimed to evaluate the capacity of coffee plants (Coffea arabica) to absorb As and accumulate the element in their vegetative and reproductive tissues, allowing inferences regarding potential risks to the food chain. The experiment was conducted in a nine-year-old coffee plantation established in a Typic Hapludox (Dystrophic Red Latosol), at the Experimental Farm of the Federal University of Uberlândia, Minas Gerais, Brazil. The treatments were arranged in a 3 × 2 + 2 factorial scheme, consisting of three As sources (arsenate, arsenic trioxide, and realgar), two application forms (powder and suspension), and two additional treatments (control and realgar in aqueous suspension), distributed in a randomized block design with three replications. The As dose corresponded to 4900 mg.plant⁻¹, simulating the accumulation resulting from successive applications of contaminated ulexite. Applications were performed around the plants within an approximately 25-cm radius at the end of the vegetative dormancy period. Before treatment application, soil, roots, and young and old leaves were analyzed to determine As concentrations. After application, young and old leaves, as well as fruits, were evaluated again. The results indicated that the soil in the experimental area had an initial As concentration of 11.3 mg.kg⁻¹, higher than that observed in a nearby native vegetation area (4.0 mg.kg⁻¹), suggesting possible enrichment associated with the agricultural history of the area. In the roots, 2.9 mg.kg⁻¹ of As was detected, whereas leaf concentrations were below the detection limit before treatment application. The application of different As sources and forms significantly influenced As accumulation in coffee leaves. The solution form resulted in higher concentrations in old leaves for arsenate (2.30 mg.kg⁻¹) and arsenic trioxide (1.87 mg.kg⁻¹), and in young leaves for arsenic trioxide (0.97 mg.kg⁻¹) and arsenate (0.87 mg.kg⁻¹), whereas realgar showed low availability regardless of the application form. The greater accumulation in old leaves and the absence of As in fruits indicate limited translocation and accumulation of the element in young and reproductive tissues. These results suggest that, although coffee plants absorb and translocate As to vegetative tissues, mechanisms restrict its transfer to fruits, even under high soil contamination, thereby reducing the direct risk associated with human consumption. In conclusion, coffee plants have the potential to absorb and accumulate As, particularly in roots and leaves, but do not exhibit relevant accumulation in coffee beans.

2026-07-30T00:00:00Z https://repositorio.ufu.br/handle/123456789/50223 2026-09-12T06:28:01Z 2026-04-09T00:00:00Z

Title: Residual do clomazona no solo e influência nas culturas do alho e cebola Abstract: The presence of herbicide residues in the soil can compromise the establishment of crops such as garlic (Allium sativum L.) and onion (Allium cepa L.) in succession systems. Clomazone, widely used in soybean as a pre-emergence herbicide, plays an important role in reducing the selection pressure of resistant weeds; however, its residual activity may negatively affect sensitive crops grown in succession. Thus, this study aimed to evaluate the residual effect of clomazone on garlic and onion, in order to determine safe intervals between herbicide application and crop planting. The experiment was conducted under field conditions in a sandy clay loam soil. The experimental design was a randomized complete block design with three blocks and seven treatments, corresponding to different intervals between clomazone application (1.5 L ha⁻¹) and crop planting: control treatment (without herbicide), 0, 30, 60, 90, 120, and 150 days after application (DAA), where DAA represents planting on the same day as herbicide application. Phytotoxicity, plant stand, plant height, and yield were evaluated. Data were subjected to analysis of variance assumptions at a 5% significance level. Subsequently, analysis of variance was performed, with stand, height, and yield compared to the control using Dunnett’s test (5%), while phytotoxicity was modeled using exponential regression with a zero asymptote. For garlic, yield did not differ significantly from the control when planting was performed from 30 days after application onwards. Exponential regression indicated a gradual dissipation of the residual effect, with the absence of visual injury symptoms estimated at approximately 75 days after application. For onion, a more sensitive crop, significant yield reductions were observed when planting occurred up to 60 DAA. Exponential regression indicated that residual phytotoxicity may persist for a longer period, with curve stabilization estimated at approximately 120 days after application. These results demonstrate greater tolerance of garlic and higher sensitivity of onion to clomazone. Under the conditions of this study, the results indicate minimum safe intervals of approximately 75 days for garlic and 120 days for onion, which may vary depending on soil texture and edaphoclimatic conditions.

2026-04-09T00:00:00Z https://repositorio.ufu.br/handle/123456789/50218 2026-09-12T06:28:11Z 2026-05-21T00:00:00Z

Title: Atributos físicos, químicos e estoque de carbono em solos de uma topossequencia sob regeneração natural no Triângulo Mineiro Abstract: This study aimed to evaluate the physical and chemical attributes of soil, as well as to quantify the total organic carbon content and carbon stock in different soil classes along a toposequence in the Triângulo Mineiro region, in the municipality of Uberaba, Minas Gerais, Brazil, in order to understand the spatial and vertical variability of these attributes and their interrelationships in soil quality. The studied toposequence was approximately 1,000 m long. The experimental design was a randomized complete block design with a split-plot arrangement, consisting of five soil classes: Oxisol (LV), Red-Yellow Oxisol (LVA), Cambisol (CA), Haplic Gleysol (GH), and Melanic Gleysol (GM), and two sampling depths (0.00–0.10 and 0.10–0.20 m), with five replicates. Physical soil attributes were evaluated, including bulk density, macro- and microporosity, total porosity, and aggregate stability and distribution, as well as chemical attributes related to soil fertility, such as pH and macro- and micronutrient contents. Total organic carbon (TOC) content and soil organic carbon stock (SOC stock) were also determined. The data were subjected to statistical analysis to identify differences among soil classes, sampling depths, and their interactions. The results showed that the hydromorphic soils, particularly the Melanic Gleysol (GM), presented higher total organic carbon contents and soil organic carbon stocks, which were associated with greater water saturation and lower rates of organic matter decomposition. In contrast, the Oxisols (LV and LVA) and the Cambisol (CA), located in higher and well-drained landscape positions, exhibited lower soil organic carbon stocks and better structural conditions. It was concluded that topography plays a decisive role in the distribution of the physical, chemical, and carbon-related attributes along the toposequence, highlighting the importance of this approach for sustainable soil management and land-use planning.

2026-05-21T00:00:00Z https://repositorio.ufu.br/handle/123456789/50009 2026-09-03T06:26:11Z 2024-11-25T00:00:00Z

Title: Características agronômicas envolvidas na adaptação de híbridos de milho em condições de primeira e segunda safra Abstract: The search for more productive corn hybrids, resistant to the main diseases that affect the crop and adapted to different sowing times, has been the target of breeding programs. The hypothesis of the research is that the sowing times affect the characteristics and productivity of corn by interacting with the environment. Thus, the aim of the research is to identify agronomic characteristics associated with the wide adaptation of corn hybrids in first and second crop conditions, in order to contribute to hybrid selection strategies by corn breeding programs. The experiments were carried out under field conditions in the 2022/23 harvest at the Corteva research station in the municipality of Indianópolis-MG. A randomized block design was used in a factorial scheme with five sowing times and sixteen hybrids, with three replications. height, ear insertion height, flowering, number of days between planting and physiological maturation, leaf length, leaf width, number of green leaves, leaf area index, severity score for Bipolaris maydis, percentage of plants with stunting, shoot dry mass (stem + leaf + ear) of corn, weight of a thousand seeds and grain yield were valued data were submitted to individual and joint analysis of variance, and when differences were observed between the treatments by the F test, the means were grouped by the Scott-Knott test. We conclude that the shoot dry mass and weight of one thousand seeds can be used to identify hybrids with wide adaptation in first and second crop condition.

2024-11-25T00:00:00Z