Avaliação de eficiência relativa para a reatividade em silicatos

Autor: Deus, Angélica Cristina Fernandes - [UNESP]
Jazyk: portugalština
Rok vydání: 2010
Předmět:
Zdroj: AlephRepositório Institucional da UNESPUniversidade Estadual PaulistaUNESP.
Druh dokumentu: masterThesis
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A eficiência dos corretivos de acidez do solo, e, sua qualidade depende da taxa de reatividade (RE), e do poder de neutralização (PN), sendo esta eficiência indicada pelo poder relativo de neutralização total (PRNT). Para os silicatos existem poucos estudos que estabeleça taxas de reatividade para suas frações granulométricas e, portanto, utilizam-se as mesmas taxas de reatividade do calcário. Foram desenvolvidos três experimentos no período de julho/2008 a outubro/2009 em casa de vegetação na Faculdade de Ciências Agronômicas/UNESP – Botucatu-SP, com o objetivo de comparar valores de reatividade das frações granulométricas para materiais silicatados em três solos de diferentes classes texturais cultivados com plantas de alfafa. Utilizou-se seis materiais corretivos: escória, silicato de cálcio, silicato de cálcio e magnésio, wollastonita, calcário dolomítico e calcário calcítico os quais no experimento 1 e 2 foram separados em quatro frações granulométricas, peneiras: nº 10 (Ø = 2 mm), nº 20 (Ø = 0,84 mm), nº 50 (Ø = 0,30 mm) e fundo (Ø
The efficiency and quality of materials for soil acidity correction are based on the reactivity rate (RR) and neutralization power (NP), and it is indicated by the effective calcium carbonate (ECC). Considering that there are few studies establishing reactivity rates of silicate particle-size fractions, lime values are used as reference. Three experiments were carried in the period July/2008 to October/2009 out in greenhouse in College of Agricultural Sciences, UNESP, Botucatu – SP, aiming to compare reactivity rates of silicate particle-size fractions in three soils with distinct textures cultivated with alfalfa plants. Slag, calcium silicate, calcium+magnesium silicate, wollastonite, dolomitic and calcitic lime were the materials evaluated. The first and second experiments consisted of four particlesize fractions obtained from each material, separated by the sieves no. 10 (Ø = 2 mm), no. 20 (Ø = 0.84 mm), no. 50 (Ø = 0.30 mm) and bottom (Ø < 0.30 mm), except that the wollastonite has the particle-size fraction < 0,30 mm. Treatments were applied in three soils: Oxisol, Hapludox and Quartzipsamment. In the first study, four doses were applied (1, 2, 4 and 8 t ha- 1) to obtain soil neutralization curve and thus determine which one was to be applied for each particle-size fraction to reach pH 5.5. The second study consisted of the application of the recommended doses from the first experiment. Then, with the pH values obtained 90 days after incubation, the relative efficiency of reactivity was calculated for each particle-size fraction based on the pH of dolomitic lime from the last sieve. Afterwards, RR and ECC were calculated. In the third study, the doses to increase soil base saturation up to 80% were calculated based on both the PRNT reported in the laboratory and in the experiment. Treatments were incubated... (Complete abstract click electronic access below)
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