Actinobacteria are a hyphae-producing soil bacteria that, in appearance and behavior, have more in common with soil fungi. The spores of Actinobacteria have a distinctive, earthy smell we often associate with rainfall. The smell comes from a compound, geosmin, which translates to "earth smell". The human nose is exquisitely sensitive to geosmin, able to detect it at concentrations down to 10 parts per trillion.

Data indicates microbes have more difficulty adapting than previously thought.

One-page primer on soil texture and soil microorganisms for the gardener. One of several soil articles from ibiblio.org.

"Teaming with Microbes", by Jeff Lowenfels and Wayne Lewis. Foreword by Elaine Ingham. Strong soil science orientation. Well organized. Extensive index. Valuable guide to labs and suppliers. Looking forward to actually reading it.

Peak Energy has a long post on Terra Preta that brings together what has been established on the subject. As of yet, there is no direct mention of the role of glomalin , just a minor mention of the mutualistic fungi that produce it. Glomalin is an unvalidated factor in Terra Preta formation that several of us sense will be demonstrated by soil research as fundamentally important. Spurred on by back40, I am fascinated with bio-char, Terra Preta's key soil amendment. Last summer I constructed a small charcoal retort out of a cracker tin. I used it to produce small pilot batches of low temperature charcoal. Hoping to transform my simple charcoal into a reasonably bio-char-like material, I am currently composting my bits.