Adsorção de fósforo e sua relação com os atributos de solos de Alagoas

Abstract

The low availability of phosphorus (P) in soils in the state of Alagoas shows the importance of studying the behavior of this element in the soil. The recommendation of phosphate fertilization for crops in the state of Alagoas has been made without taking into account the adsorption characteristics of these soils. The objective of this work is to know the values of the Maximum Phosphorus Adsorption Capacity (MPAC) and the relationships with the other soil attributes to define the P rates to be applied in the crops. In this sense, eleven soil samples representing the regions of Sertão, Agreste and Litoral Alagoano 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, different forms of Fe and Al and MPAC values defined by the Langmuir isotherm. Correlations and regressions were made between the MPAC values and the other physical and chemical soil attributes. The results showed that the MPAC values ranged from 999.0 to 133.0 mg kg-1 of P in the soil. Soil attributes that showed a significant correlation with MPAC were P-Remaining, Organic Matter, Cation Exchange Capacity (CEC), potential acidity (H+Al), Clay and Fe and Al contents complexed by Organic Matter. Therefore, they estimate the value of MPAC and influence the behavior of phosphorus in the soil. Keywords: adsorption of phosphorus; soil of Alagoas; remaining P.