Glad you discovered Dr. Ingham! She is a well known and somewhat controversial figure. She and her followers seem to have figured out how to game Google. When you do a Google search on Elaine Ingham, the results that come up, three pages deep (as far as I looked) are all from her, her Institute, her followers and fans, with no other viewpoints represented. The Wiki article about her is a nothing, lists the posts she has held and the books published, period.
I am an organic/ natural gardener and I believe very much of what Ingham has said. If you check our book discussion section, here viewforum.php?f=43 we did an extensive review of Jeff Lowenfels - Wayne Lewis book "Teaming with Microbes," which is all about the soil web of life. I do grow all of my plants with no synthetic fertilizers, only compost, compost tea AND mulch. I think Dr Ingham with her insistence that the soil feeds itself through the actions of microbial life doesn't pay enough attention to mulch. You should read Ruth Stout's no work gardening books (out of print but available on line) for a different perspective about growing everything heavily mulched. Both of them agree that tilling is very destructive. Mulch holds moisture in the soil, which Ingham agrees is very important to keep the microbes functioning. But also as it breaks down mulch adds more nutrients to the soil.
Where I part company with Ingham is the idea that once you have helped set up a functioning microbial web in the soil, you can quit adding nutrients. Sorry, but everything you grow takes nutrients out of the soil. Yes, the microbial life can continue to create some nutrients by breaking down mineral elements in the soil, but there is a limit to the quality and quantity that can be produced that way. Ultimately, it will need more inputs. Personally, I am constantly adding mulch and compost to my soil.
In nature, everything is a cycle, born/sprouted, grow, die, become compost. But in the natural cycle nothing is removed. The food that is grown in one location is eaten and pooped back out in the same location and the creatures that ate the food die and are composted in that location. We do not have a system like that. I try to make my backyard as much a closed loop as I can. But still that means that everything I grow is either eaten or returned to the soil (unfortunately, I don't have a composting toilet to help complete the loop!). That means all the organic wastes are either composted or mulched and returned to the soil. That is necessary to keep the cycle going. Without continually adding the compost and mulch back to the soil, you don't have a loop any more, you have an outflow that will eventually be exhausted.
She and her followers are true believers who think they have the one truth. I am always suspicious of that.