Found it!
http://permaculturenews.org/20...
Yup, key words being "biologist", "biological" and "microbial life". I had seen one of her YouTube videos, I think the very one in that link.
Again, I agree 100% that soil (as distinct from hydroponic growing media) NEEDS organic matter to start with, and enough to be added every year to replace what was digested. Otherwise no microbes, worms or insects can grow in it, and plants' roots are much less healthy and effective (for example, because mycorrhizae can't thrive and penetrate plant root hairs).
...
Dr. Elaine Ingham
"Dr. Ingham is a world-renowned soil biologist who pioneered many of the currently used biological soil amendment techniques and pioneered the testing of soil microbial life as an indicator of soil and plant health. Dr. Ingham is the Chief Scientist at the Rodale Institute."
"Dr. Ingham is the key author of the U.S. Dept. of Agriculture’s Soil Biology Primer."
