Our results showed that: i) mechanical chiseling of clayey soil under NT, in humid subtropical climate region, does not affect soil organic carbon content in the profile from 0 to 0.30 m depth; ii) mechanical chiseling of clayey soil under NT decreases the size and stability of soil aggregates, in the layer 0.07 to 0.17 m, in the first six months after this practice; iii) the positive effects promoted by soil mechanical chiseling on soil physical attributes (penetration resistance, macroporosity and bulk density) and root development (root density) expired three crops after this operation; iv) root development in depth, intensified in the first crops after mechanical chiseling, is not enough to promote improvement in the soil aggregation state in the compacted sub-superficial soil layer (0.07 to 0.17 m) in areas under NT; and v) mechanical chiseling of clayey soil under NT does not promote effective and long lasting improvements in the soil structure, in humid sub-tropical climate region.