Movimentação de cálcio de diferentes fontes adicionadas em colunas de dois Latossolos

• Ano de defesa: 2006
• Autor(a) principal: Figueiredo, Getúlio Coutinho
• Orientador(a): Ruiz, Hugo Alberto
• Banca de defesa: Fernandes, Raphael Bragança Alves , Neves, Júlio César Lima
• 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: Calcário; Gesso; Wollastonita
• Palavras-chave em Inglês: Limestone; Gesso; Wollastonita
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5461

With the objective of evaluating the vertical mobility of Ca in response to the incorporation as NO3-, SO4 2-, SiO3 2-, and CO3 2- in two Latosols of contrasting texture, after application of irrigation depths, a laboratory trial was conducted using soil columns. The treatments corresponded to a 2 (1 + 7) factorial design involving two Latosols of Minas Gerais (Yellow Latosol and Red Latosol), one control (application of deionized water) and seven stoichiometrically equal Ca sources: Ca(NO3)2.4H2O, CaSO4.2H2O, CaSiO3, CaCO3, ½ CaSO4.2H2O + ½ CaSiO3, ½ CaSO4.2H2O + ½ CaCO3, and ½ CaSiO3 + ½ CaCO3. Each experimental unit was represented by a soil column of 2.4 dm3, placed in a recipient that consisted of ten assembled 7 cm high PVC rings. The Ca source, as very fine particles, was uniformly incorporated into the soil contained in the three superior rings. The Ca doses were equivalent to 3.9 and 7.0 t/ha of CaCO3 for the Yellow Latosol and Red Latosol, respectively. Enough deionized water was then applied to attain the maximal water-holding capacity in equilibrium with the force of gravity, and the soil columns incubated for 7 d. Thereafter, five depths of deionized water of 50 mm each were applied every 6 d and the leachate collected. The leachates and the soil contained in each ring were analyzed. Results allowed the ranking of the Ca movement in the soil profile in response to the anion as follows: NO3- >> SO4 2- >> CO3 2- > SiO3 2- The magnitude of Ca mobility depended on the soil texture composition and was greater in the Yellow Latosol (medium texture) than the Red Latosol (very clayey). The differentiated mobility was further associated to the higher water solubility of Ca(NO3)2.4H2O, followed by CaSO4.2H2O and to the formation of the ionic pair CaHCO3+. Moreover, CaCO3 and CaSiO3, in decreasing order, corrected the soil acidity in the application layer. After the application of the 250 mm of deionized water, CaCO3 movement was observed in the columns, presenting a response of correction of the soil acidity down to 7 cm beneath the application layer. CaSO4.2H2O reduced the soil pH little and provoked the displacement of aluminum in solution, as indicated by the presence of this cation in the leachate. Of the analyzed mixtures, the one composed of CaCO3 and CaSO4.2H2O was the most appropriate to correct the harmful effects of soil acidity in depth.