I agree with you on starting at ground zero…..those are pioneer conditions. There’s a process in soil rebuilding that is just like clear cutting a forest……..over the years you’re going through more and more changes that are working toward “climax” conditions……we’re talking about in terms of structurally, chemically, and biologically………If you keep resetting the process and don’t allow it to progess then you’re keeping yourself in those pioneer conditions. The true fertility comes more and more as you move toward those climax conditions. Once you get things out of the gutter the idea is to simply help nature along and much of the time just stay out of the way. We spend a lot of effort fighting against the grain. These pics were taken probably 10 years ago or more…..the spots painted orange are crabgrass roots. The bottom of the hole is 48 inches deep and the soil pH in that layer is 5.0