http://localhost:8080/handle/prefix/49 2026-11-10T02:31:37Z 2026-11-10T02:31:37Z Evald, Ariane http://localhost:8080/handle/prefix/181 2019-07-29T05:00:05Z 2016-04-29T00:00:00Z

Title: Qualidade do solo na cultura do arroz cultivado em várzea roraimense Autor(es): Evald, Ariane Primeiro Orientador: Melo, Valdinar Ferreira Abstract: The search for sustainable agriculture has promoted the development of research in the soil field aimed at understanding the behavior that soil presents in response to different managements and crops. A large number of researchers has focused its efforts on identifying soil properties that are more efficient in inferring soil quality due to soil changing as result from use and management. The aim presented in this study was to evaluate the soil quality by chemical properties, soil microbiological and biochemical in an area with waterlogged rice cultivation under different years of cropping. The areas have the following rice cultivation times (1, 3, 8, 13 and 25 years) compared to a nature area (reference). Composite samples with four replications were collected at 0-10 cm depth. They were separated into two sub-samples, one for chemical analysis and one for microbiological and biochemical analysis, which were stored under cooling. In the laboratory the chemical attributes evaluated were: soil organic carbon (SOC), total nitrogen (TN), P available, K+, Ca2+, Mg2+ exchanges, Al3++H+ exchanges and pH, and calculated the CEC, and C/N ratio. The microbiological attributes were: microbial biomass carbon (MBC), microbial respiration (MR), calculated the CO2 coefficient (qCO2) and microbial coefficient (qMIC). The enzymes activities of acid phosphatase and urease were evaluated. The different years of rice cultivation were significantly different from the nature area in most of the soil indicators assessed, with higher expressivity, especially to SOC, NT, P, CBM and acid phosphatase variables. In the principal component analysis was observed the formation of two main groups of components (CP). SOC, C-BMS and NT were the main variables of the CP1, the acid phosphatase indicators, Mg2+ and P were the variables of greater expressiveness in CP2. The abrupt shift in soil quality from nature area converted to rice cultivation decreased the soil quality, but after 8 years of rice cropping the soil presented an improvement in soil quality. Publisher: Universidade Federal de Roraima Tipo: Dissertação

2016-04-29T00:00:00Z Espinoza Guardiola, Marden Daniel http://localhost:8080/handle/prefix/180 2019-07-26T05:00:06Z 2016-03-09T00:00:00Z

Title: Atributos químicos e matéria orgânica do solo sob diferentes sistemas de uso e manejo em ambientes de floresta de Roraima Autor(es): Espinoza Guardiola, Marden Daniel Primeiro Orientador: Vale Júnior, José Frutuoso do Abstract: The crop-livestock integration systems (cLI) crop-livestock integration forest (cLIF) and pasture have emerged as strong alternative to carbon incorporation and consequently improvement in physical and chemical characteristics of the soil. The objective of this work to evaluate the chemical attributes, organic matter in soils under Natural forest undertaken in different use systems and soil management: pasture (PAST), crop-livestock Integration (cLI) crop-livestock Integration forest (cLIF) and a Natural forest (NF) as a witness. The experimental design was completely randomized in plots scheme subdivided, with 24 treatments from the association between four systems and six different depths (0-10, 10-20, 20-40, 40-60, 60-80 and 80-100 cm), with four repetitions. The data subjected to analysis of variance, and significance through "F", the averages compared by Tukey test at 5% probability of error. cLI systems and PAST showed similarities in chemical attributes such as pH, Ca2+, Mg2+ and K+. pH showed no difference between the studied systems. For potential acidity (H + Al) the highest value for this variable was found in the cLIF area at a depth of 0-10 cm and the smallest in the pasture. Aluminum (Al3+) was superior in the NF. The sum of the bases (SB) presented the highest value in the PAST system. The saturation by bases (V %) was higher in the PAST in all the depths evaluated, and lower in the NF. The total cation exchange capacity (TCC), showed the highest value in the area of cLI in the depths 0-10 and 10-20 cm and the smallest values in the cLIF area at the depth of 20-40 cm. The chemical fractionation of soil organic matter (SOM) revealed that the cLIF area had the major value for Humina (HUM) and humic Acid (HA). The FN presented greater value for Fulvic acid (FA). The NF presented the largest value for Fulvic acid (FA). The particulate organic carbon (Cop) was greater at all depths in the PAST area. The organic carbon associated with minerals (Coam) presented the highest value for all systems in general in the 0-10 cm depth. The total organic carbon (TOC) was greater among the systems assessed in relation with the NF. Oxidizable fractions showed similar values in the lighter fractions (F1) and (F2), however, regardless of the evaluated area, it observed a predominance of the most recalcitrant fractions of MOS (F3) and (F4). The analysis of carbon stocks showed no significant difference but presented best values between systems in relation to FN. After this results, its concluded that management systems deployed showed higher values of Ca2+, Mg2+, Na+, and P in the surface layer (0-10 cm) of soil in relation to the NF. Humic substances (HA), (HUM) and the physical fractions (Coam) showed greater stability in management systems. The ratio AH/AF was greater in the PAST area and a reduced amount of in the cLI indicating that organic matter from ecosystems presents greater stability on the ground. The (HUM) showed higher levels, regardless of the area studied and analyzed depths. Therefore, the management systems evaluated positively influenced in the dynamics of the MOS when compared with NF. Publisher: Universidade Federal de Roraima Tipo: Dissertação

2016-03-09T00:00:00Z Sousa, Debora Dinelly de http://localhost:8080/handle/prefix/179 2019-08-03T05:00:06Z 2013-08-28T00:00:00Z

Title: Caracterização genética dos vírus dengue sorotipo 1 isolados em Roraima durante os anos de 2008 a 2010 Autor(es): Sousa, Debora Dinelly de Primeiro Orientador: Acosta, Pablo Oscar Amézaga Abstract: In northern Brazil, Roraima is highlighted as one of the dengue virus hyperendemic states, where the four serotypes has been circulating for the last three years and with a high incidence of this disease in the last decade. On the other hand, its geographic localization has an important part on the entry of new genotypes/serotypes of dengue in Brazil. DENV-1, after a short incursion in the state in years 1981 and 1982, was reintroduced in 2000 and it was one of most isolated serotypes until 2011. Nevertheless, there is little data that shows the occurrence of genetic variability or any evolution in genetic composition from this serotype on infections occurred in different years. The objective of this project was to perform a molecular characterization of the envelope gene isolated from DENV-1 on infections occurred between 2008 and 2010 in Roraima. The samples were inoculated in C6/36 cells from Aedes albopictus, and identified by indirect immunofluorescence and RT-Hemi-Nested-PCR techniques. To obtain an amplicom from the envelope region, it was made an RT-PCR test with specific primers, generating a product with 1724 bp. The amplicons were sequenced and the consensus sequences were obtained using the program Geneious V.5.5.4. For molecular analysis, the current sequences were compared to sequences from the four serotypes of dengue virus and also compared to five genotypes of DENV-1 from different parts of the world available on GenBank. The phylogenetic reconstruction was made by two methods, Maximum-likelihood and Bayesian. All of the isolates were grouped in genotype V of DENV-1. The sequences showed 99-100% of similarity with strains of DENV-1 from neighbor countries and states as the Bolivarian Republic of Venezuela, Guyana, Colombia and Amazonas, they were grouped on a phylogenetic tree forming a subclade with strains of these countries and Caribbean region, and besides indicating, once more, Roraima as a possible entry route of serotypes/genotypes of dengue in Brazil, fact totally proven in 2010 with the entry and dispersion of genotypes II of DENV-4. The Brazilian strains of genotype V of DENV-1 formed three distinct lineages. The isolates of this study (2008-2010) were grouped in lineage III, different from the strain that circulated in the state in 2001, which belonged to lineage II. When these sequences were compared, it was found four aminoacid substitutions, two of them (E428 e E436) probably neutral which did not change tridimensional conformation of the envelope, since amino acids with similar physicochemical characteristics were changed (Leucine x Valine; Isoleucine x Valine), and two substitutions (E227 e E338) with high probability of changing the envelope (Proline x Serine; Leucine x Serine). These results may indicate an adaptive evolution of DENV-1 or the entry of a new lineage in the State, emphasizing the importance of molecular monitoring strains of DENV in circulation in certain regions, allowing better understanding of the virus. Publisher: Universidade Federal de Roraima Tipo: Dissertação

2013-08-28T00:00:00Z Maldonado, Selvin Antonio Saravia http://localhost:8080/handle/prefix/178 2019-07-24T05:00:05Z 2017-07-14T00:00:00Z

Title: Qualidade do solo em sistema de pastagem convertida ao cultivo de dendê (Elaeis guineenses Jacq.) Autor(es): Maldonado, Selvin Antonio Saravia Primeiro Orientador: Cordeiro, Antonio Carlos Centeno Abstract: The oil palm is a crop that has great economic potential, since its producti ve potential is extremely high, being culti vated in several countries of Asia, Africa and America. In Brazil, its culti vation is concentrated in only a few regions, distributed mai nly in the Northeast and North of the country. However, in spite of the few areas with commercial culti vation, the oil palm presents potential of planting due to the advantage of being able to intercalate different species, with emphasis on the recovery of altered areas and forest fragments. The objecti ve of this work was to study the soil quality in a pasture system converted to palm oil (Elaeis guineenses Jacq.), Under i ntercropping, established in an experimental area of Embrapa, i n the municipality of São João da Baliza, Boa Vista - RR, vicinal 26, Km 12, with geographic reference coordi nates 00º 51' 13,3''N and 60º 00' 19,8''W and an altitude of 100 m, i nstalled on a Red-Yellow Argisol. The planting systems had dimensions of 36 mx 39 m, formi ng a total area of 1,404 m². The experimental design was completely randomi zed, in a subdi vided plots scheme with 4 replicates for the chemical and physical analyzes, and completely randomi zed with 4 replicates for the microbiological and biochemical analyzes. The treatments consisted of 5 systems intercalated with palm, being: 1) i ntercalated with grass, Brachiaria h umidicola (DP); 2) pineapple, C v. Victory (DA); 3) Cowpea, Cv. Guariba (DF); 3) banana, Cv. Japira (DB); 4) cassava, C v. Amazonas (DM) and 5) grass, Brachiaria humidicola (PS). The physical and chemical attributes were evaluated in the layers 0-0.10 ; 0.10-0.30 and 0.30-0.50 m and i n the 0-0.10 m layer for the microbiological and biochemical attributes. It was found a heavier granulometry for the DM, DB and P systems which in turn presented higher formation and stabilization of aggregates denoted by high DMG, DMP and IS i ndexes, covering all this, under balanced macro and micropore conditions, i ncreases in total porosity and decrease of soil density. The highest values of pH, exchangeable Ca2+, Mg2+, K+ and the decrease of Al3+ i n the DM e DF intercalations s ystems were observed for all the layers evaluated, with high levels in the sorption complex, SB, C TCt and V. The area PS presented low ferti lity, originating from its natural conditions. Meanwhile, the systems that showed the best results and that contributed most to improve the soil microbiological and biochemical conditions were PS, DP and DM, positi vely influencing variables C-BMS, qCmic and the enzymatic activities of β-glucosidase, urease and acid phosphatase. Publisher: Universidade Federal de Roraima Tipo: Dissertação

2017-07-14T00:00:00Z