I'm working on a project in which the response of the soil microbiome under water limitation is measured, using three diverse soils with distinct edaphic characteristics. We aren't working with plants (at least to start out with). My question is, is there any consensus on the right soil RWC (or range of RWC values) across soils to induce drought stress? We can easily design experiments to further narrow this down, I'm hoping to figure out where to start and what is a good target.