Data/hora: 11/06/2024 12:06:44

Provedor de dados: | 90
País: | Brazil
Título: | Kinetics of K release from soils of Brazilian coffee regions: effect of organic acids
Autores: | Silva,Vladimir Antônio; Marchi,Giuliano; Guilherme,Luiz Roberto Guimarães; Lima,José Maria de; Nogueira,Francisco Dias; Guimarães,Paulo Tácito Gontijo.
Data: | 2008-04-01
Ano: | 2008
Palavras-chave: | Successive extractions; First order; Zero order; Parabolic diffusion; Elovich.
Resumo: | Kinetic studies on soil potassium release can contribute to a better understanding of K availability to plants. This study was conducted to evaluate K release rates from the whole soil, clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State, Brazil. Potassium was extracted from each fraction after eight different shaking time periods (0-665 h) with either 0.001 mol L-1 citrate or oxalate at a 1:10 solid:solution ratio. First-order, Elovich, zero-order, and parabolic diffusion equations were used to parameterize the time dependence of K release. For the Oxisol, the first-order equation fitted best to the experimental data of K release, with similar rates for all fractions and independent of the presence of citrate or oxalate in the extractant solution. For all studied Ultisol fractions, in which K release rates increased when extractions were performed with citrate solution, the Elovich model described K release kinetics most adequately. The highest potassium release rate of the Ultisol silt fraction was probably due to the transference of "non-exchangeable" K to the extractant solution, whereas in the Oxisol exchangeable potassium represented the main K source in all studied fractions.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000200008
Editor: | Sociedade Brasileira de Ciência do Solo
Relação: | 10.1590/S0100-06832008000200008
Formato: | text/html
Fonte: | Revista Brasileira de Ciência do Solo  v.32 n.2 2008
Fonte: | info:eu-repo/semantics/openAccess