A common sight in past autumns was the cultivation of soybean or corn stubble after harvest. This was accomplished with disk cultivators (like this one) plowing the ground under with the organic material deposited a few inches below the surface while exposing new soil to air and water. Resultant organic recycling leads to a superior seed bed preparation with the side benefit of cleaner looking fields.
But in the late 1980s this practice was phased out for better methods of soil management. Up until that time precious topsoil was often eroded by wind or water which did no one any good. Today fields are generally chisel planted as to be minimally impactual on soil. However there are times when it is necessary to till, such as when soil compaction is discovered, for optimized planting.
These rusting disks show remnants of some of the best soil in America for grain production. Proper soil management is as important as the annual harvest itself. Many farmers already know that.