Atributos químicos e mineralógicos de óxidos de ferro de latossolos submetidos a diferentes estresses químicos

• Ano de defesa: 2011
• Autor(a) principal: Gusmão, Lina Kesi
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; UEM; Maringá, PR; Programa de Pós-Graduação em Agronomia
• Palavras-chave em Português: Solos; Mineralogia; Química do solo; Óxidos de ferro; Susceptibilidade magnética; Atributos mineralógicos do solo; Maghemita; Magnetita; Minerais ferrimagnéticos.; Mineralogical soil attributes; Maghemite; Magnetite; Ferrimagnetic minerals; Magnetic susceptibility.; Ciências Agrárias; Agronomia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1184

The aim of this study was to use magnetic attributes (mass specific magnetic susceptibility (xLF) and frequency-dependent magnetic susceptibility (xFD)) to evaluate changes in the ferrimagnetic iron oxides (magnetite and maghemite) mineralogy of ten Oxisols after adding organic residues and different redox conditions. The soils after their chemical, physical and mineralogical characterization were used in two experiments. The first experiment was used to determine the optimum sample volume for xLF and xFD determination in three situations: solely soil, soil + sugar up to 10cm3 and soil + sugar up to 20cm3. In a second experiment three Oxisols received four organic wastes (sewage sludge-BIO, laundry sludge-LAV, swine manure-CHO and vinasse-VIN) and two redox conditions (free drainage-DL and saturated soil-SS) where it was evaluated xBF and xDF for 37 weeks. In the first experiment, the results showed that the greater the amount of ferrimagnetic minerals in the sample the lower the volumes of material necessary for determining the xBF and xDF values. The soil volume (VM) where occurs the determination of the highest values of VM-xFD and VM-xBF vary with the mass of soil available for analysis. In the case of xBF using only soil we obtained values of MV~12cm3, while the dilution to 10cm3 of soil resulted in values of MV~7.3cm3. The dilution to 20cm3 of soil resulted in values of MV>10cm3 for most soils. For the xFD values, the soil volume required may be less than 10cm3 and greater than 3cm3. The levels of total iron (Fet) area related to the xBF values, but do not to the xFD. In the second experiment it was possible to conclude that the mass specific magnetic susceptibility (xBF) and frequency-dependent magnetic susceptibility (xFD) were able to evaluate changes in the ferrimagnetic iron oxides mineralogy in soils with free drainage and/or saturated. The saturated soil (SS) condition in most soils and wastes applied determined xBD values associated with the formation of maghemite. There was an increase in the amounts of cBF in some treatments with free drainage showing that ferrimagnetic minerals synthesis in soils is an ongoing process. The soil chemical properties also exert influence on the dynamics of ferrimagnetic iron oxides in soils. The levels of total iron (Fet) and aluminum extract with sodium dithionite-citrate bicarbonate (Ald) showed correlations with the xFD and xFD values. The addition of organic wastes alters the xLF and xFD values and the intensity of this change was different for each soil and redox conditions (LL and SS).