Characterization of phosphorus adsorption in soils of Rio Grande do Norte

Abstract

In representative soils of two regions in Rio Grande do Norte State: Noncalcic Brown, Podzolic, Latosol, Lithosolic and Vertisol, phosphorus levels were added for determination of adsorption parameters. The values obtained were graphically represented in Langmuir isotherm form and showed high linear correlations for P-solutions between 0.7 and 11.9 x 10^-4M, in soils of the sandy loam texture and to values higher than 1 x 10^-4M in clayey soils. The Langmuir equations, maximum adsorption, estimated adsorption to phosphorus solutions at 0.1 or 0.2 ppm and bonding energy were to be determined. The Podzolic and Latosol soils showed the values of maximum adsorption, around 70 ppm. The highest value was showed in Vertisol soil, 1,075 ppm.