It causes them
I think you’re confused
they can, for sure.
Corn rowing appears most commonly on carpets made from fine, soft yarns, with a fairly high cut pile. In most cases the overall density is not adequate to support the yarns and keep them upright. If there is too much space between the rows, the tufts may be bent over when they are walked on. Soft, fine yarns do not spring back as readily as other carpet yarns made from heavier and denser fibers.
Corn rowing may appear on carpet before or after cleaning. It usually forms in a regular pattern with every fourth or fifth row of yarns bending over, as might happen in a field of corn. The condition may develop in traffic lanes and under doors that scrape the carpet as they are opened and closed. It generally occurs perpendicular to the traffic direction.
Although cleaning the carpet may make corn rowing apparent, it is not the cause of the distorted pile surface. Corn rowing is simply an inherent characteristic of certain carpet constructions. Vacuuming and raking the carpet perpendicular to the traffic patterns may help in some cases. In extreme situations, we suggest you contact the manufacturer.