One minor point of clarification: they talk about the soil profile - in backyard settings this has been removed, and then topsoil has been brought in so you're left with 4 inches of topsoil over your C horizon. The topsoil you have is not the topsoil that was there.

A great resource is the cannabis cultivation podcast with Tad Hussey of KIS Organics. They cover all things organic, including building up a healthy soil rhizosphere, which is how the whole soil ecosystem breaks down nutrients so they're plant available.

It's definitely focused on organic cannabis growing, but it goes heavily into general garden practices both indoor and outdoor.