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Provedor de dados:  Ciência e Agrotecnologia
País:  Brazil
Título:  Adsorption and availability of phosphorus in response to humic acid rates in soils limed with CaCO3 or MgCO3
Autores:  Maluf,Henrique José Guimarães Moreira
Silva,Carlos Alberto
Norton,Lloyd Darrell
Rosa,Sara Dantas
Data:  2018-02-01
Ano:  2018
Palavras-chave:  Organic ligands
Humic acid-metal-P complexes
Langmuir isotherm
Phosphate maximum buffering capacity.
Resumo:  ABSTRACT Humic acid (HA) may reduce adsorption and increase soil P availability, however, the magnitude of this effect is different when Ca2+ prevails over Mg2+ in limed soils. The objective of this study was to evaluate the effects of HA rates and carbonate sources on the adsorption, phosphate maximum buffering capacity (PMBC), and P availability in two contrasting soils. Oxisol and Entisol samples were firstly incubated with the following HA rates: 0, 20, 50, 100, 200 and 400 mg kg-1, combined with CaCO3 or MgCO3, to evaluate P adsorption. In sequence, soil samples were newly incubated with P (400 mg kg-1) to evaluate P availability. The least P adsorption was found when 296 mg kg-1 of HA was added to Oxisol. Applying HA rates decreased maximum adsorption capacity, increased P binding energy to soil colloids and did not alter PMBC of Entisol. Available P contents in Oxisol increased with HA rates, but it did not change in Entisol. Choosing the right HA rate can decrease PMBC up to 40% and increase the Oxisol P availability by 17%. Application of MgCO3 instead of CaCO3 decreased P adsorption in both soils. Thus, a positive correlation between Ca2+ content and PMBC was verified. Optimum rate of HA and the preponderance of Mg2+ instead of Ca2+ in soil volume fertilized with P are effective practices to reduce adsorption and increase P availability, especially in clayey Oxisol.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Editor:  Editora da Universidade Federal de Lavras
Relação:  10.1590/1413-70542018421014518
Formato:  text/html
Fonte:  Ciência e Agrotecnologia v.42 n.1 2018
Direitos:  info:eu-repo/semantics/openAccess

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