In silty soils of the Argentinean Humid Pampas cropped under no tillage (NT), platy soil structure is widespread and constrains water entry and transfer into the topsoil. Many authors have attributed this to planes of weakness induced by traffic compaction. The most extensive cropping system has high soybean frequency in the rotation, which results in frequent harvesting during fall on wet soils only sparsely covered by crop residue. Our objective was to test the hypothesis that traffic and the presence of crop residues influence platy structure development. A five-year field experiment was started in 2005 at INTA Pergamino, Buenos Aires, Argentina, on a Typic Argiudoll which had been cultivated under NT for the previous five years. After initial characterization of the soil structure, two traffic levels (Tf /NTf) were applied to four crop sequences: soybean monoculture, maize-wheat/soybean succession, same succession with residues exportation, bare soil. The soil structural state was assessed using the cultural profile approach, and bulk density, pore size distribution, pore origin distribution, aggregate stability, total C and shear strength were determined for each type of soil structure. At the start of the experiment, platy structure was absent and the topsoil was constituted of 95% of gamma (Γ) and 5% of delta (∆) structures. In crop successions, the top centimeters were dominated by a granular structure, irrespectively of the surface residues cover. The proportion of platy structure then increased until covering about 50% of the A horizon after 5 years, irrespective of the traffic or presence of crop residues, and the Γ structure was proportionally reduced. Soil surface structure evolution under NT was thus marked by the rapid development of platy structure to the detriment o f the Γ structure in all situations analyzed, which suggests that the traffic and the presence of crop residues are not critical factors for platy structure development in silty soils of the Argentinean Humid Pampas.