Gênese, mineralogia e dinâmica do fósforo nos solos do Planalto Ocidental Paulista
Carregando...
Data
2017-07-27
Autores
Gomes, Romário Pimenta [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nos solos tropicais, o fenômeno de adsorção de fósforo é regido pela mineralogia da fração argila, que, por sua vez, é afetada pelo material de origem e intensidade de dissecação da paisagem. Desse modo, objetivou-se relacionar o fósforo total e adsorvido com principais minerais da fração argila dos solos do Planalto Ocidental Paulista, São Paulo, associando com a geologia e o grau de dissecação da paisagem. Foram selecionadas cinquenta e cinco amostras de solo representativas da variabilidade fisiográfica do Planalto Ocidental Paulista, na profundidade de 0,0 – 0,2 m, para a caracterização das formas de fósforo, mineralogia da argila por difração de raios-x (DRX) e espectroscopia de reflectância difusa (ERD); utilizou-se também calibração quimiométrica através da regressão de mínimos quadrados parciais (PLSR). Verificou-se que o P total e o P adsorvido são influenciados pela geologia e grau de dissecação da paisagem, e são covariativos dos óxidos de Fe e Al, sendo esses óxidos importantes indicadores de ambientes com maiores e menores potenciais de adsorção e com baixos e altos teores de P. A caracterização das curvas espectrais permite diferenciar o conteúdo de P total com base na mineralogia da fração argila. A análise por regressão de mínimos quadrados parciais (PLSR) dos dados espectrais evidencia a influência dos óxidos de ferro no conteúdo de P total e adsorvido, sendo a Hm ao P total e a Gt ao P adsorvido.
In tropical soils, the phenomenon of phosphorus adsorption is governed by the mineralogy of the clay fraction, which in turn is affected by the material of origin and intensity of dissection of the landscape. the objective was to relate the total phosphorus and adsorbed with the main minerals of the clay fraction of the soils of the Planalto Ocidental Paulista, associating with the geology and the degree of dissection of the landscape. Were selected fifty - five soil samples representative of the physiographic variability of the Planalto Ocidental Paulista, in the depth of 0.0 - 0.2 m, for the characterization of phosphorus forms, clay mineralogy by X - ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS); it was also used chemometric calibration Through the partial least squares regression (PLSR). It was verified that the total P and adsorbed P are influenced by the geology and degree of dissection of the landscape, and are covariate of the Fe and Al oxides, and these oxides are important indicators of environments with higher and lower adsorption potentials and with low and high levels of P. The characterization of the spectral curves allows to differentiate the total P content based on the mineralogy of the clay fraction. Partial least squares regression analysis (PLSR) of the spectral data shows the influence of iron oxides on the total and adsorbed P content, with Hm at the total P and Gt at the adsorbed P.
In tropical soils, the phenomenon of phosphorus adsorption is governed by the mineralogy of the clay fraction, which in turn is affected by the material of origin and intensity of dissection of the landscape. the objective was to relate the total phosphorus and adsorbed with the main minerals of the clay fraction of the soils of the Planalto Ocidental Paulista, associating with the geology and the degree of dissection of the landscape. Were selected fifty - five soil samples representative of the physiographic variability of the Planalto Ocidental Paulista, in the depth of 0.0 - 0.2 m, for the characterization of phosphorus forms, clay mineralogy by X - ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS); it was also used chemometric calibration Through the partial least squares regression (PLSR). It was verified that the total P and adsorbed P are influenced by the geology and degree of dissection of the landscape, and are covariate of the Fe and Al oxides, and these oxides are important indicators of environments with higher and lower adsorption potentials and with low and high levels of P. The characterization of the spectral curves allows to differentiate the total P content based on the mineralogy of the clay fraction. Partial least squares regression analysis (PLSR) of the spectral data shows the influence of iron oxides on the total and adsorbed P content, with Hm at the total P and Gt at the adsorbed P.
Descrição
Palavras-chave
Hematita, Goethita, Espectroscopia de reflectância difusa, PLSR, Adsorção de P, Hematite, Goethite, Diffuse reflectance spectroscopy, Adsorption P