Data/hora: 08/06/2024 09:37:08

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; Curi,Nilton; Norton,Lloyd Darrell; Rosa,Sara Dantas.
Data: | 2018-02-01
Ano: | 2018
Palavras-chave: | Organic ligands; Liming; 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
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542018000100007
Editor: | Editora da Universidade Federal de Lavras
Relação: | 10.1590/1413-70542018421014518
Formato: | text/html
Fonte: | Ciência e Agrotecnologia  v.42 n.1 2018
Fonte: | info:eu-repo/semantics/openAccess