QUALIDADE FÍSICA DO SOLO NA DIAGNOSE DA COMPACTAÇÃO E NA AVALIAÇÃO DA AGRICULTURA REGENERATIVA

Abstract

Soil compaction is a major form of physical degradation, severely impacting soil functions essential for agricultural productivity and environmental sustainability. In Brazilian tropical soils with contrasting textures, defining reference values for physical attributes is crucial for structural diagnosis and management planning. This study aimed to model soil compaction in a sandy soil (73 g kg⁻¹ clay) and a very clayey soil (823 g kg⁻¹ clay), proposing reference bulk density (Bd) values associated with beneficial or critical structural conditions. Undisturbed soil samples were subjected to uniaxial compression tests, with structural changes quantified through Bd, least limiting water range, porosity, and mechanical pressures (σp, σb, and σl). Results indicated a severe water availability limitation in the sandy soil and high compaction susceptibility in the very clayey soil. The inverse relationship between clay content and Bd reference values allowed for the refinement of pedotransfer functions tailored to specific textural classes. Following this, the study assessed the impact of regenerative agriculture as a sustainable management strategy to mitigate compaction and improve water infiltration and groundwater recharge in the Brazilian Cerrado. Field assessments were carried out in nine plots across eight farms in southwestern Goiás, using a Regenerative Agriculture Index (RAI) based on five core management principles. Undisturbed soil samples were collected at three depths (surface, shallow, and moderately shallow layers) and evaluated for bulk density, porosity, saturated hydraulic conductivity (K₀), air permeability (Kear), and water retention. Soil compaction diagnosis was performed using region-specific pedotransfer functions. The results showed initial improvements in surface layer physical quality under higher regenerative management levels, but subsurface compaction remained a significant constraint. Multivariate analysis identified macroporosity as the key attribute distinguishing structural conditions. The RAI had a modest yet positive influence on soil hydraulic conductivity and relative density. The study concludes that while regenerative agriculture has potential to restore tropical soil physical quality, its effectiveness is correlated with longer adoption periods and comprehensive implementation of its principles, especially crop diversification.