Atributos físicos do solo em resposta à adição de efluente tratado de indústria de celulose

• Ano de defesa: 2008
• Autor(a) principal: Almeida, Ivan Carlos Carreiro
• Orientador(a): Fernandes, Raphael Bragança Alves
• Banca de defesa: Rocha, Genelício Crusoé , Silva, Gualter Guenther Costa da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: Água residuária; Eucalipto; Salinidade do solo
• Palavras-chave em Inglês: Residual waters; Eucalyptus; Soil salinity
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5411

The disposal of effluents from the cellulose industry in soil can be an attractive option for the use of these residual waters since it is an additional process to the existing treatment systems as well as provide a supplemental source of water and nutrients for the plants. Therefore, the objective of this study was to evaluate the effect of application of these cellulose industry effluents on the physical attributes of the soil. Three experiments were performed: one in the field (experiment I) and two in the laboratory (experiments II and III). Experiment I was setup in an experimental area of a forestry company, conducted in Fluvic Neossol soil, where four different treatments had been applied to a eucalyptus plantation for six years: irrigated, non-irrigated, with fertirrigation and with the application of effluents from the cellulose plant. A nearby pasture area was used as a reference. Soil samples from each of the different treated areas were evaluated for: penetration resistance, hydraulic conductivity (k0) in the field and in the laboratory, routine chemical analyses, texture, geometric mean diameter (GMD) and weight mean diameter (WMD) of aggregate, water-dispersible clay (WDC), dispersion index (DI), bulk density (BD), total porosity (PT), microporosity (Mi), macroporosity (Ma), organic carbon (OC), least limiting water range (LLWR) and the sodium absorption ration (SAR) in the saturated paste extract (SPE). The obtained results indicated the increase of BD in the eucalyptus plantation, and the consequent reduction of the PT and K0 (laboratory). The applied effluent promoted the reduction in the GMD and WMD of the aggregates and increase in the DI, which can be associated with the increase in the Na levels, with the consequent increase of the SAR verified in the soil and in the SPE for this treatment. In experiment II (laboratory), a test using PVC columns filled with soils was setup in triplicate, with the goal of evaluating the effect of the surface application of treated effluent from the cellulose industry for a period of five weeks on the physical characteristics of the soil and the leaching recovered at the base of the columns. Three predominant soils from the region of the forestry company were used to fill the columns: Fluvic Neossol (RY), Haplic Cambisol (CX) and Yellow Latosol (LA). The columns were then submitted to the application of four different treatments (effluent, effluent+water, water and water+water), formed by the weekly addition of equivalent liquid volumes to a volume of pores for each soil class. At the end of the experiment, the columns were dismounted and the soil dived into three parts (upper, middle and lower), each section being separately analyzed for the evaluation of textures, routine chemical characteristics and WDC. In the SPE obtained from these samples the levels of Ca, Mg, Na, K, pH, electrical conductivity (EC) were determined and the SAR was calculated. From the leaching collected after the each applications, Ca, Mg, Na, K, P, Cd, Cr, Pb, Ni, Zn, Mn, Al, pH and EC were determined. The obtained results indicated that the addition of the effluent increased the level of Na in the leaching, in the SPE and in the sortive complex of the soil. The applied effluent also caused increases in the pH in all layers of the soil in the column, and in the EC of the SPE. The addition of water after the application of the effluent showed to be capable of reducing the levels of Na in the system and, consequently, the values of ESP, EC and SAR, however the values considered ideal were not reached. The addition of the effluent increased the clay dispersion in the upper layer of the LA and CX, coinciding with soils of lesser natural DI. The RY soil showed no significant dispersion with the addition of the effluent and from its leaching, greater levels of cations were obtained, which was associated to its greater particle size. In experiment III (laboratory), the effect of successive treated effluent applications from the cellulose industry on K0 of samples from the same three soil types previously mentioned. Undeformed soil samples, contained in volumetric rings, were submitted to weekly evaluation, for a period of five weeks, of the K0 during the application of water or effluent. After the evaluation period was completed, the samples were submitted for the evaluation of WDC, Ma, Mi, PT, BD and moisture content equivalent. The obtained data showed the effect of the application of the effluent on the hydraulic conductivity for LA, for which the addition of residual water reduced the values of K0. No other evaluated characteristic in the soils presented significant alteration with the liquids applied. The results of the three experiments conduction indicate the potential use of effluents as an alternative water source for eucalyptus, however, due to its high concentration of Na+ and potential for clay dispersion, its use should be carefully managed and under the control of a soil monitoring program.