Soil factors affecting phosphorus adsorption in soils of the Cerrado, Brazil

Abstract

This study aimed to determine the maximum phosphorus adsorption capacity (MPAC) in seven distinct soil classes from the Brazilian Cerrado and to evaluate possible interactions with soil chemical and physical properties by principal component analysis (PCA). The sampled were collected from the depth ranges of 0.0 to 0.20 and 0.20 to 0.40 m and then analysed. First, remaining phosphorus (Prem) content was determined. Then, P doses to be added to solutions were estimated. Finally, MPAC was evaluated using the Langmuir equation. The MPAC varied considerably among seven distinct soil classes (from 72 to 928 mg kg−1 de P at two depth ranges 0.0–0.20 and 0.20–0.40 m). The variation was significantly correlated with the clay, silt, organic matter, iron available and binding energy. The use of only clay content for phosphorus interpretation and recommendation in soils may lead to errors in the soil fertility management, especially in Cerrado soils, as a function of the complexity of the interactions involved in the process. Principal component analysis can be a useful tool for understanding the dynamics of the soil MPAC, as it is sensitive in discriminating the studied soils.