http://repositorio.ufc.br/handle/riufc/110 Wed, 10 Jun 2026 14:09:17 GMT 2026-06-10T14:09:17Z http://repositorio.ufc.br/handle/riufc/86069 Título: Espectroscopia de reflectância vis-NIR-SWIR-MIR na caracterização de perfis e avaliação de atributos de solos típicos do Nordeste do Brasil Autor(es): Souza, Francisca Evelice Cardoso de Abstract: Soil is essential for life on Earth and for the performance of ecosystem services, making efficient monitoring of its attributes essential. Traditionally, soil is evaluated through wet chemistry laboratory analyses, but this technique has proven to be costly and time consuming. As a promising alternative, remote sensing using reflectance spectroscopy stands out for allowing rapid and low cost pedological analyses, which is especially advantageous for the study of heterogeneous regions susceptible to degradation, such as Northeast Brazil. Given this context, the objectives of this study were: to explore the potential of visible to mid-infrared spectra to characterize the spectral behavior of soils in the Northeast region; to quantify the physical and chemical attributes of these soils, including salinity and sodicity, using spectroscopy in the 350 - 15000 nm range and multivariate statistical algorithms. A total of 114 soil samples were evaluated, covering nine orders, collected from 24 soil profiles distributed across 13 cities in Ceará. Through wet chemistry analyses, the following attributes were determined: organic carbon, total nitrogen, available phosphorus, exchangeable potassium, calcium, magnesium, sodium, and aluminum, electrical conductivity, pH, base sum, cation exchange capacity, base saturation, and sodium saturation percentage. Spectral analysis evaluated soil reflectance in the visible, near infrared, short wave infrared (vis-Nir-SWIR), and mid infrared (MIR) ranges, with data preprocessed using Savitzky Golay smoothing and conversion to absorbance. The results of the conventional analysis were evaluated using descriptive statistics. The smoothed data were subjected to principal component analysis (PCA), and the PCA scores were used for cluster analysis with the unsupervised Fuzzy K means classification algorithm. To quantify the attributes, predictive models were developed with raw and preprocessed spectra using Partial Least Squares Regression, Support Vector Machine with linear and radial kernel functions, and Cubist Algorithm algorithms. The performance of the predictive models was evaluated by the metrics R², RMSE, RPD, and RPIQ. The results of the qualitative analysis rev ealed spectral behaviors with distinct patterns between soil orders. Unsupervised classification grouped samples based on horizon characteristics, with the MIR region showing greater sensitivity to identify more subtle variations between horizons. In the quantitative analysis, all attributes were predicted with at least satisfactory performance, except for calcium, which showed unsatisfactory performance with R² below 0.50. The models developed with MIR data consistently outperformed those in the vis NIR SW IR range for most attributes. The predictions of electrical conductivity and sodium saturation percentage showed reasonable performance, highlighting the potential of the technique for diagnosing soil salinity and sodicity. These highlighting the potential of the technique for diagnosing soil salinity and sodicity. These results confirm the potential of reflectance spectroscopy as an efficient and alternative tool for characterizing and predicting attributes in heterogeneous soils. Tipo: Tese Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86069 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85669 Título: Mineralogia do saprolito e manejo de áreas no Núcleo de Desertificação de Irauçuba, Ceará: relações com a pedogênese de planossolos Autor(es): Silva, Francisco Gilcivan Moreira Abstract: Food production and the consequent food security of vulnerable populations in arid and semiarid regions of underdeveloped countries in Asia, Africa and South America are limited by the climatic, environmental and socioeconomic characteristics of these regions. This worrying situation has been worsened by the variation of climate change in recent years. An example of this scenario can be observed in the most densely populated semiarid underdeveloped region in the world, located in northeastern Brazil, which faces serious problems in agricultural production due to limitations caused by climatic and soil conditions, resulting in the process of desertification in some places. However, restoration practices (e.g. fallowing) are promising to contain desertification and eventually improve soil functioning. However, the understanding of the effect of fallowing, the genesis and mineralogy of soils under desertification still remain poorly understood. Therefore, in this work we integrated pedology and management with the aim of expanding knowledge about the genesis of Planosols originating from a gneiss rock in a desertified area in the semiarid climate, in addition to verifying the effect of fallow on the weathering evolution of the profile in relation to a forested area and another overgrazed area. The experiment was conducted in a desertification center in the municipality of Irauçuba, in the semiarid region of Brazil, where we performed a morphological description of the soil profiles and collected undisturbed and disturbed samples of soil and saprolite, in three profiles, one located in an area under fallow practice for 20 years, another in an overgrazed area and the last in a forested area. Then, chemical and physical analyses were performed, in addition to mineralogical and micromorphological analyses for the purpose of classification and determination of the genesis and weathering evolution of the soil. The results indicated that fallow promoted considerable changes in the surface horizons, with an increase in organic matter and improvement of the soil structure. The granulometry reflected the influence of management on pedogenesis. Mineralogical analysis showed the predominance of aluminosilicate minerals and the presence of primary minerals, decreasing the importance of clay in the pedogenetic process. Micromorphology revealed the presence of biotite and feldspars in the installation process. However, the type of management did not significantly influence the weathering rates. Therefore, it is possible to conclude that the pedogenetic process is predominantly clay-based, with several biotite and feldspar minerals disintegrating, although a level of clay deposition was observed in the particles of the Bt horizon of all areas. Using weathering indices, it is shown that the type of management does not significantly influence the weathering rates of the areas. Tipo: Tese Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85669 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83645 Título: Sistema consorciado e adubação verde como práticas conservacionistas para produção de moringa Autor(es): Silva, Elizio Sampaio da Abstract: Moringa (Moringa oleifera Lam.) is considered a subsistence crop found in areas with different soil types, cultivated in regions with low-income populations. With multiple purposes and adapted to semiarid conditions, it can be intercropped to increase farmers’ income, serving as an alternative in the bioeconomy. It is necessary to define the best intercropping strategy with green manure legumes, aiming at greater sustainability in M. oleifera production on sandy soil. It is assumed that intercropping moringa with a species adapted to water deficit, and subjected to partial pruning for green manure purposes, constitutes a management practice to improve soil fertility and generate income for farmers. The study was carried out in Beberibe (CE), under rainfed conditions. The experimental design was a randomized block design with split plots and four replications. In the plots, two types of pruning of the intercropped plants (50% and 100% of the total plants) were evaluated, and in the subplots, two intercropped species (pigeon pea and leucaena) were assessed, along with spontaneous vegetation. Biomass production of the intercropped species and spontaneous vegetation was evaluated, determining nutrient and sodium accumulation. Soil chemical attributes were assessed after pruning, as well as moringa oil yield, pigeon pea grain production, and leucaena biomass. The economic viability of the intercropping system was investigated. A normality test was conducted, with transformation applied to data not showing normal distribution, followed by analysis of variance, and when significant differences were found, Tukey’s test was used for mean comparisons. In nutrient accumulation analyses for biomass, pigeon pea produced more dry matter and accumulated more macro- and micronutrients, with native vegetation surpassing it in zinc accumulation. In the 0–20 cm soil layer, for 50% pruned plants, pigeon pea provided better results for P, Na, CO, and Ca, CEC, sum of bases, and V%, while spontaneous vegetation resulted in higher Cu content under 100% pruned plants. In the 20–40 cm soil layer, spontaneous vegetation showed higher values for Ca content, CEC, sum of bases, and V%, while in pigeon pea, soil acidity and Mn stood out. Regarding root development in the influence area of intercropped plants, root surface area in spontaneous vegetation was greater beyond 80 cm from moringa. In the pigeon pea area, at 20 and 60 cm distances, greater total root length and root weight were observed, respectively. Soil N content was higher in the pigeon pea intercrop at 20 cm from moringa. Considering moringa oil production, greater profitability was observed in the moringa–leucaena intercrop with 100% pruned plants. Tipo: Tese Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/83645 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83368 Título: Salt acclimation and ionic homeostasis are associated with priming and memory in rice plants Autor(es): Sotero, Allana Rayra Holanda Abstract: This thesis aimed to test the hypotheses that the pre-exposure of rice plants to eustressors in the early stages of life can generate stress memory. This memory would be responsible for promoting more efficient metabolic responses under salt conditions and to achieve an acclimation state faster. Thus, the first part of the thesis consists of a contextualization on the importance of studies on soil salinity and rice production for food security. Then, a brief review of concepts of great relevance in the context of research, such as acclimation and stress of plants, as well as the concepts of eustress and priming and their relevance in the scientific environment. Subsequently, we started the experimental part, seeking to identify salinity dose capable of promoting eustressor effects in rice plants. For this, we conducted an experiment with different salinity doses (low - 16 mM NaCl; moderate - 25 mM; and high - 50 mM) applied in exposure-recovery cycles to identify possible differences in the responses due to stress repetition, as well as the spatial effect of ionic accumulation on tissues. The results indicate that saline doses from low to moderate, when applied in the vegetative phases, present potential for stress memory formation. So, the exposed plants have morphological alterations in relation to the control plants, yet without severely compromising crop productivity. From the results of this first experiment, a second experiment was carried out using moderate salinity (25 mM NaCl for 7 days) as priming agent at different stages of plant development to identify the effect of application time on metabolic and morphological responses. The tested treatments were priming during germination and during traditional transplanting moment (V6) followed by saline stress (50 mM NaCl), imitating the actual condition of exposure of seedlings after transplanting. As a result, we obtained that the seed priming (SPS) presented high beneficial potential for the crop. Despite reduction in leaf length, there was an increase in dry biomass production and tillering compared to the control treatment. On the other hand, the priming treatment applied at the time of transplanting (VPS) showed a strong distressor effect, with lower parameters than those obtained by the salt stress treatment alone (S). In addition, it was possible to visually identify the premature necrosis of the flag leaf tissues, although they did not present toxic ions' accumulation. Together, the results of these studies show the great phenotypic plasticity of rice, presenting differential responses in each tissue and adapting according to the moment of exposure to the stressful factor, stress intensity, acclimation state. More studies are needed related to the epigenetic part to unravel the mechanisms behind this plasticity, considering the space-time scale of these organisms with such complex and dynamic behavior. Tipo: Tese Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/83368 2025-01-01T00:00:00Z