INTERPRETATION OF SOIL PROFILE ARCHITECTURE THROUGH MEAN, LINEAR, QUADRATIC, AND CUBIC TRENDS IN A RHODIC FERRALSOL UNDER DIFFERENT MANAGEMENT SYSTEMS IN THE BRAZILIAN CERRADO

Abstract

The impacts of management on soil profile architecture can be assessed through the behavior of macroaggregate, mean weight diameter, and organic carbon coefficients throughout the profile. This study aimed to interpret the profile architecture of a Rhodic Ferralsol under different management systems in the Brazilian Cerrado using the mean (p₀), linear (p₁), quadratic (p₂), and cubic (p₃) trends of macroaggregates, mean weight diameter (MWD), and organic carbon. Data from the 0–5, 5–10, 10–20, 20–30, and 30–40 cm soil layers were analyzed under native Cerrado, eucalyptus, pasture, no-tillage, heavy disk harrowing, and disk plowing. The vertical trajectories of the indicators were described by orthogonal polynomial regression. The integration of the polynomial trends revealed distinct profile architectures among management systems, even when their mean conditions were similar. Systems subjected to less mechanical disturbance showed greater continuity between structural organization, aggregate stability, and the organic component, whereas recurrent soil tillage promoted greater differentiation of trajectories with depth. Heavy disk harrowing reflected the influence of tillage interruption and the subsequent fallow period on structural reorganization, whereas disk plowing showed the strongest expression of mechanical interference with the vertical organization of macroaggregates. Thus, polynomial trends distinguished the mean condition, direction, curvature, and inflection points of the indicator trajectories, demonstrating that systems with similar mean values may exhibit distinct profile architectures. Soil profile architecture reflected the nature, intensity, duration, and succession of management interventions, revealing soil as a dynamic system undergoing continuous transformation and adjustment to environmental conditions.