Please use this identifier to cite or link to this item: https://repositorio.ufu.br/handle/123456789/45254
ORCID:  http://orcid.org/0009-0008-6852-0965
Document type: Dissertação
Access type: Acesso Aberto
Title: Sensitivity of cationic micronutrient extractors to pH elevation in cerrado soils
Alternate title (s): Sensitivity of cationic micronutrient extractors to pH elevation in cerrado soils
Author: Gomes, Caio César Sales
First Advisor: Santos, Wedisson Oliveira
First member of the Committee: Batista, Araína Hulmann
Second member of the Committee: Azevedo, Lucas Carvalho Basílio de
Third member of the Committee: Barreto, Matheus Sampaio Carneiro
Summary: The application of acidity correctors to soils redistributes geochemical species of Zn, Cu, Mn, and Fe between fractions available and unavailable to plants, through processes affected by pH variation, such as precipitation by hydrolysis, dispersion of organic matter, adsorption desorption dynamics and changes in the interfacial properties of colloids. However, the sensitivity of traditional chemical extractors to these geochemical changes has not been sufficiently elucidated, especially in highly weathered systems. The aim of this study was to evaluate the sensitivity of different extractors to the increase in soil pH induced by liming and to identify changes in the chemical species of cationic micronutrients. The experimental design followed a 2 × 7 factorial scheme, involving two types of soil representing the main pedogenetic classes in Brazil (Latossolo and Neossolo) and seven levels of correction with CaCO₃ (0-, 0.25-, 0.50-, 1.0-, 1.5-, 2.0- and 2.5-times the H+Al content of the soils). The treatments were arranged in randomized blocks with three replications. After stabilizing the active acidity of the soil (pH), the Cu, Fe, Mn and Zn contents were determined using four extractants (Mehlich-1, Mehlich-3, KCl and DTPA). The behavior of the extractants varied due to their different mechanisms for accessing the chemical species. Mehlich-1 proved to be insensitive to an increase in soil pH because it is acidic and the pH of the extracting solution does not undergo significant changes after contact with the soil, leading to the dissolution of hydrolyzed species, while DTPA was sensitive to an increase in pH, probably because its complexation constants with nutrients did not exceed the precipitation-dissolution constants, limiting the dissolution of precipitated species. KCl showed low efficiency in recovering Zn, Cu, Mn and Fe, probably due to the predominance of non-exchangeable species, which makes it apparently insensitive to pH changes. The variable behavior of Mehlich-3 stems from its multiple extraction mechanisms. To assess the availability of nutrients in the short term, DTPA stood out as the most suitable extractant for quantifying the available levels of Zn, Cu, Mn and Fe for plants.
Abstract: The application of acidity correctors to soils redistributes geochemical species of Zn, Cu, Mn, and Fe between fractions available and unavailable to plants, through processes affected by pH variation, such as precipitation by hydrolysis, dispersion of organic matter, adsorption desorption dynamics and changes in the interfacial properties of colloids. However, the sensitivity of traditional chemical extractors to these geochemical changes has not been sufficiently elucidated, especially in highly weathered systems. The aim of this study was to evaluate the sensitivity of different extractors to the increase in soil pH induced by liming and to identify changes in the chemical species of cationic micronutrients. The experimental design followed a 2 × 7 factorial scheme, involving two types of soil representing the main pedogenetic classes in Brazil (Latossolo and Neossolo) and seven levels of correction with CaCO₃ (0-, 0.25-, 0.50-, 1.0-, 1.5-, 2.0- and 2.5-times the H+Al content of the soils). The treatments were arranged in randomized blocks with three replications. After stabilizing the active acidity of the soil (pH), the Cu, Fe, Mn and Zn contents were determined using four extractants (Mehlich-1, Mehlich-3, KCl and DTPA). The behavior of the extractants varied due to their different mechanisms for accessing the chemical species. Mehlich-1 proved to be insensitive to an increase in soil pH because it is acidic and the pH of the extracting solution does not undergo significant changes after contact with the soil, leading to the dissolution of hydrolyzed species, while DTPA was sensitive to an increase in pH, probably because its complexation constants with nutrients did not exceed the precipitation-dissolution constants, limiting the dissolution of precipitated species. KCl showed low efficiency in recovering Zn, Cu, Mn and Fe, probably due to the predominance of non-exchangeable species, which makes it apparently insensitive to pH changes. The variable behavior of Mehlich-3 stems from its multiple extraction mechanisms. To assess the availability of nutrients in the short term, DTPA stood out as the most suitable extractant for quantifying the available levels of Zn, Cu, Mn and Fe for plants.
Keywords: fractionation
methods
micronutrients
soil ph
fracionamento
métodos
micronutrientes
ph do solo
Area (s) of CNPq: CNPQ::CIENCIAS AGRARIAS
Subject: Agronomia
Language: eng
Country: Brasil
Publisher: Universidade Federal de Uberlândia
Program: Programa de Pós-graduação em Agronomia
Quote: GOMES, Caio César Sales. Sensitivity of cationic micronutrient extractors to pH elevation in cerrado soils. 2025. 38 f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Uberlândia, Uberlândia, 2025. DOI http://doi.org/10.14393/ufu.di.2025.5081.
Document identifier: http://doi.org/10.14393/ufu.di.2025.5081
URI: https://repositorio.ufu.br/handle/123456789/45254
Date of defense: 25-Feb-2025
Sustainable Development Goals SDGs: ODS::ODS 15. Vida terrestre - Proteger, recuperar e promover o uso sustentável dos ecossistemas terrestres, gerir de forma sustentável as florestas, combater a desertificação, deter e reverter a degradação da Terra e deter a perda da biodiversidade.
Appears in Collections:DISSERTAÇÃO - Agronomia

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