Evaluation of phosphorus adsorption in a sandy-loam soil in Perugorria, Corrientes

Abstract

The study analyzes phosphorus adsorption in a sandy loam soil in the town of Perugorría, located in the southern part of the province of Corrientes, in the fifth section of the department of Curuzú Cuatiá. Samples were taken at a depth of 20 cm and characterized through physicochemical analyses. Phosphorus adsorption was evaluated at different concentrations and temperatures (5, 30, and 45 °C). The results showed low adsorption, with values ranging between 17.81% and 26.19%. This indicates that a significant portion of phosphorus remains in solution, increasing the risk of leaching and runoff. Adsorption was found to be favored by higher temperatures, leading to an increase in distribution constants (KD) and the organic partition coefficient (KO.C.). This suggests a greater interaction with soil organic matter. The adsorption isotherm analysis showed that the Langmuir model fits better than the Freundlich model, indicating that adsorption occurs at specific sites rather than in multiple layers. The thermodynamic parameters revealed that the process is spontaneous and endothermic, with an increase in entropy. This suggests that phosphorus mobility is enhanced at higher temperatures. It is concluded that due to the soil's low adsorption capacity, improving fertilization management is crucial to minimizing losses by leaching and maximizing phosphorus availability for plants. This optimization will enhance crop productivity and promote agricultural soil sustainability.