>> I'm glad that I only have to amend for nutrients and not for texture.
That's great!
I'm fumbling my way toward a theory about how to make good soil. It would have stages or aspects of soil that must be satisfied.
Mechanical
Chemical
Biological
Interdependent (holistic)
1. Mechanical structure
Grain sizes, drainage, aeration, friability and "tilth". The grains and fibers need to be coarse enough to allow both drainage and retention (excess water drains out, but enough is held between rains) and aeration (air can perk in and CO2 can perk out).
Stickiness may help or hurt: it might help form beneficial crumbs or make clay so sticky and dense that nothing can pry it apart, Soil must not be so sticky that it is not friable.
There is something like "stiffness" that allows soil to "stand up" around a void instead of slumping and flowing to fill the void. I think that is the opposite of "pliable".
Grain shapes that are elongated and twisty and interlock help prop the soil up better than ball-bearing-shaped grains that wash out easily so that they flow into voids and fill them .
Mechanical structure could be completely inorganic, except for the facts that roots add structure, and the breakdown products of organic matter (and worm castings) probably help soil 'clump' and form into 'crumbs' or peds.
We usually talk as if healthy soil forms discrete crumbs that sit on top of each other like golf balls, with continuous, connecting open spaces between balls of soil.
My theory instead is that "crumb structure" should be called "interstice structure". I think that, when soil is appropriately sticky, it gloms together so as to support many small, individual crevices and voids that don't necessarily interconnect, but instead scatter and wind through a mostly continuous phase of solid soil.
Like ponds and short streams dotting a solid landscape. Not like islands of soil spotting a continuous ocean.
When we try to build "crumb structure", we're actually trying to make the little voids stable enough that they don't slump or shrink out of existence.
