Isotermas de adsorção de langmuir para fósforo em solos de Alagoas

Abstract

The low incidence of phosphorus in the soils of the state of Alagoas shows how important it is to study the behavior of this element in the soil. The recommendation of phosphate fertilization for crops in the State of Alagoas has been made without considering the adsorption characteristics of the soil. The objective of this study is to know the Maximum phosphorus adsorption capacity (MPAC) values and the relationships with other soil attributes, such as clay, P- remnant, Cation exchange capability (CEC), Al and Fe contents by the Langmuir isotherm models. In this context, 11 soil samples representing the State of Alagoas, Sertão, Agreste and East Alagoas regions were collected, in the 0-20 cm layer, to determine the physical attributes (sand, silt and clay), chemical attributes (pH, P, K, Na, Ca, Mg, H+Al, organic matter, CEC), remaining P, Fe and Al determined by sodium dithionite-citrate-bicarbonate and ammonium oxalate and the values of Maximum P Adsorption Capacity, defined by the Langmuir isotherm. The best result found and described by the models studied was with model 2 of the Langmuir isotherm, as we observed in the literature several references of the Langmuir model obtaining satisfactory results on other isotherms.

Keywords: Phosphorus Adsorption; P- Remnant; Langmuir.