Mestrado em Agronomia (EA)
URI Permanente para esta coleção
Navegar
Navegando Mestrado em Agronomia (EA) por Por Orientador "CAMPOS, Alfredo Borges de"
Agora exibindo 1 - 2 de 2
Resultados por página
Opções de Ordenação
Item Efeitos da aplicação de glifosato na química de solos alagados(Universidade Federal de Goiás, 2010-09-10) BELTRÃO, Danielle Silva; FERNANDES, Eliana Paula; http://lattes.cnpq.br/7324619074753727; CAMPOS, Alfredo Borges de; http://lattes.cnpq.br/3249635044992714This study aimed to evaluate the effects of the herbicide glyphosate in the chemistry of the flooded soils in two humid tropical areas included in the Brazilian savanna, observing these effects in the solid fraction and the soil solution. We used soil from an area of lowland irrigated rice cultivation and a preserved area of path, constituting, respectively, a disturbed area under agriculture and a preserved area with natural vegetation. The soils were subjected to varying periods of saturation, and applying different doses of glyphosate. The treatments were: a) Dosage: Dose 0, dose 1 (1.6 mg L-1), Dose 2 (16.0 mg L-1), Dose 3 (1600.0 mg L-1) and b) periods of saturation solutions: 1, 7, 15, 30 and 60 days. The soils were previously saturated with solutions of glyphosate prepared with distilled and deionized water, and only distilled and deionized water to dose 0, for 2 hours. After that time the volume was completed with distilled deionized and deoxygenated water. At the end of each period of saturation of soil redox potential was determined in intact experimental units, as well as the pH of the solutions after separation by centrifugation. Proceeded to freezing at - 20 ° C of the soils and soil solutions for chemical analysis and a fraction of the solutions was wrapped and refrigerated at 4 º C for later, perform the analysis of dissolved organic matter. The freezing and cooling were performed to inhibit the biological activity in the degradation of glyphosate and organic matter according to the literature. Before the analysis of the solutions we proceeded to filter membrane syringe filter to 0.45 mm in PVDF (polyvinylidene fluoride), 33 mm in diameter. Chemical analysis of soil were taken for determination of pH 0.01 M CaCl2, micronutrients (Cu, Fe, Mn and Zn), P, K, available Ca and Mg, Al, H + Al and organic matter. Chemical analysis of the solutions were limited to the determinations of Cu, Fe, Mn, Zn, K, Ca, Mg and Al and was carried out to determine the E4/E6 ratio for the humification of DOM in UV-Vis spectrometer. The different effects of glyphosate were used as the ground, showing the influence of soil characteristics and attributes in the interaction with the herbicide. The solid fraction in the analysis highlighted the effects of doses 2 and 3 in lowland soil and dose 3 in solo path. Glyphosate conferred resistance to the reduction of metals in soil and floodplain had the highest effect on the availability Eh redox sensitive elements as Fe and Mn. In the path the herbicide soil favored the reduction of metals from soil and has provided these elements. In soil solution, for the more concentrated doses, there was decreased solubilization of Fe and Mn and other elements, and affect differently the organic matter in soils, occurring in the path of higher aliphatic DOM, ie, less degradation of biological effect of dose 3. The two three doses of glyphosate and, occasionally, the first dose, influenced the chemistry of the lowland soil. The dose 3 showed more significant effects on the soil of trail. The effects of doses 1 and 2, corresponding to the doses used in the field, are highlighted as important outcomes of this study.Item Uso de nitrogênio no cultivo de arroz irrigado e seus efeitos no solo, na planta e na emissão de óxido nitroso(Universidade Federal de Goiás, 2011-02-15) CARVALHO, Glaucilene Duarte; FAGERIA, Nand Kumar; http://lattes.cnpq.br/1794909905335127; CAMPOS, Alfredo Borges de; http://lattes.cnpq.br/3249635044992714In wetland soils are countless electrochemical changes, among the most influenced by anaerobic conditions is nitrogen. The rice crop also determine changes in the process, either by the nutrient uptake or by changes in the rhizosphere. The nitrogen can guarantee high yields of rice, however, due to the inadequate use of nitrogen can have nitrous oxide, which is a greenhouse gas. In this context, the research aimed to determine the effects of nitrogen fertilizer in flooded lowland soils in soil chemistry and soil solution on the plants and the emission of nitrous oxide. The experiment was conducted in pots at Embrapa Rice and Beans. The treatments consisted of two rice genotypes (BRS Tropical and BRA 051130) and three nitrogen (0, 150 and 300 mg N kg-1 soil). The experimental design was randomized blocks with split plots. The flooding of the vessels took place on the fifteenth day after planting. The collection solution was given 1, 3, 7, 14, 28, 39, 59, 67, 102 days after flooding. The collection system consisted of a perforated plastic pipe and secured in the vessel walls, being closed at the ends. The solution was suctioned through a syringe and then analyzed on Ca, Mg, K, P, Fe, Mn, NO3 -, NH4 +, pH and Eh (directly to the pots). After the experiment was made at the soil sampling vessel, comprising all the other treatments being performed analysis of Ca, Mg, K, P and soil pH. The yield components studied were: plant height, tiller number, panicle number per plant, panicle length, spikelet sterility, dry weight of 1000 grains, shoot dry weight, root dry mass, grain yield, root length, grain harvest index, the contribution of the shoot dry weight total contribution of root dry weight total. The method of collection of nitrous oxide was a closed chamber in PVC material. Collections were undertaken throughout the rice cycle and N2O concentration was measured by reading in a gas chromatograph. The results were subjected to analysis of variance, treatment means compared by Tukey test. The pH, exchangeable Ca, Mg, K and P in soil increased after the implementation of the experiment. The values of Eh in soil solution decreased with time of flooding and consequently the pH increased. The concentration of Ca and Mg in soil solution increased with time of flooding and the K, Mn, NO3 -, NH4 + declined over the period. The rice genotypes showed differences in dry weight of 1000 grains. The dry weight of shoots showed responses to nitrogen fertilization, since the height of the trees showed responses to genotypes and N levels The total emission of N2O showed differences in nitrogen use and for the rice genotypes. We observed that the genotype BRA 051130 showed significantly higher total emission in relation to the treatment without plants.