Phosphorus adsorption in soils of tropical regions

Abstract

Phosphorus (P) is the most limiting nutrient for cultivation in tropical soils, as they generally have high P adsorption capacity. Some chemical and physical attributes of soil such as clay content, pH, effective cation exchange capacity (ECEC) and organic matter influence the adsorption dynamics. The objective of this study was to evaluate the behaviour of the phosphorus adsorption process in a Red-Yellow Latosol and a Quartzarenic Neosol from the Cerrado-Amazon transition region, and to evaluate the soil attributes that influence the adsorption dynamics of the soil of the phosphorus. Sorption tests were performed using the “Bach” method, from the Langmuir linearized equation, the maximum P adsorption capacity (MPAC), the constant with the binding energy (KB) and the maximum capacity factor (PCFmax) were selected. There was a difference in MPAC, KB and PCFmax of the studied soils, and the highest values were found in the Red-Yellow Oxisol, mainly due to the higher clay content in relation to theTypic Quartzipisamment. Organic matter was one of the few attributes that had a negative correlation with the adsorption attributes, highlighting (emphasizing) it’s importance in (soil) management to increase the efficiency of phosphate fertilization.