Farming turfgrass benefits soil compared to other types of farming because it not only 1) decreases erosion to almost zero, it also 2) builds topsoil. Erosion occurs when the elements of nature (wind, rain, etc.) wash or blow away nutrient-rich topsoil. When topsoil is washed away, any chemicals that have been used on the area wash away with it, gathering in ditches, streams, and rivers. On a sod farm, the erosion is almost zero, even after a really heavy rain, and even on areas where grass was recently harvested – the roots of the grass are just below the surface, clinging to topsoil and preventing erosion.
Erosion occurs in backyards too. Avoid the mistake of having your yard landscaped for sod before waiting several weeks before installing. It is important to install turf ASAP on newly landscaped ground, because rain or wind can create ditches and ruts and can wash or blow topsoil away.