What Do Your Soil and Your Body Have in Common?

a-microscopic-viewMy family attended a nice presentation at The Natural Gardener in Austin this morning, called “Connecting Soil Health to Human Health.” This is a topic we’ve been especially interested in recently, and we are digesting all of the information we can find on this topic. The presenters were Stuart Nunnally, DDS,MS,NMD from Marble Falls; with J.R. Builta and Betsy Ross from Sustainable Growth Texas. We thought it was a really nice and relevant discussion, so I wanted to pass on the main points here…

The big picture is that carbon is out of balance in much of our soil. And Because 95% of what we eat originates in the soil, this imbalance is passed on to us through our food. All organic material contains carbon, and in a well-balanced ecosystem most of the carbon is sequestered in the soil. Many of our modern activities result in more and more carbon escaping the soil and entering the atmosphere. These activities include paving the ground, planting inappropriate plants (like turf grass), leaving disturbed soil exposed to the sun and air, using antimicrobial products in our yards and homes, spraying pesticides, spraying herbicides, and using synthetic fertilizers to “fake” a fertile soil. These things we do tip the balance in our environment, so that more and more carbon is released from the earth into the atmosphere.

All soil-borne life sequesters carbon. The more we disturb that life, the more carbon is released into the air. Once carbon has been released into the atmosphere, we rely on plants to filter it from the air and return it to the soil. As we disturb more forests and grasslands, less and less carbon is filtered out from the air. It’s some pretty basic biology. And it is a real world feedback loop that has the potential to spiral out of control.

Betsy Ross explained the issue by paraphrasing Dr. Christy Jones, the Australian Soil Ecologist, that there are two “broken bridges” we can repair that will correct this problem. The first broken bridge is the “photosynthesis bridge,” and we can repair this bridge by doing three things – 1) leave no bare ground, 2) plant native plants and incorporate native evergreens, and 3) use only natural products. Fixing this “bridge” restores the ability of the environment to filter carbon from the air. The second broken bridge is the “microbial bridge,” and we can repair this bridge by doing 2 things – 1) use plants that favor mycorrhizal fungi, and 2) manage the complete soil food web by applying appropriate aerobic compost tea. Fixing this second “bridge” restores the ability of the environment to sequester carbon in the ground.

We learned about how the plants that grow in a soil influence that soil’s biological profile. Bermuda grass, for instance, prefers a soil with relatively high bacterial activity and relatively low fungal activity. And where bermuda grass takes hold and prospers, it will cultivate this profile in the soil. Native shrubs and vines prefer a soil with slightly more fungal activity than bacterial activity. Where those plants grow, they will cultivate an active fungal profile in the soil. In order to restore carbon sequestration to a sustainable level, J.R. Builta proposed a two-pronged approach: first, plant appropriate plants that will cultivate a balanced soil profile; and second, apply compost tea that is formulated to support a balanced soil profile that is appropriate for your desired plants. This graphic is from Sustainable Growth Texas. It shows the appropriate soil biology profile for a range of different plants. F = Fungus and B = Bacteria, and the values are given as a ratio of F:B. As you see, the “sweet spot” we’re shooting for is the well-balanced bubble between 0.75 and 5:1.


There are natural environments on earth that run the gamut from highly bacterial to highly fungal soil profiles. But when we plant monocultures that rely on synthetic fertilizers and biocides – in corn fields, in lawns, etc. – we can essentially wipe out the soil profile, so that few of the natural soil-borne organisms survive. In this environment carbon escapes the soil in mass, and pathogens thrive below the ground.

Dr. Nunnally took the microphone to discuss the human health aspect of the discussion. The first parallel he drew between human health and soil health was hydration. One of the most obvious effects of mismanaged soil is that it dries out very quickly. It’s impossible to maintain a healthy microbial environment in dehydrated soil – and it’s no different for a dehydrated human body. Dr. Nunnally discussed how pathogens are normally present in both healthy soil and healthy human guts – about 5% of the bacteria in healthy soil are pathogens, and as much as 15% of the bacteria in a healthy human gut are pathogens. But in a healthy system, pathogens are kept in check by the community of beneficial organisms, never amassing enough numbers to cause an infestation (soil) or an infection (gut). He compared soil supplements to human nutrient supplements. In both cases, supplements can be used to triage serious deficiencies, but in both cases supplements are not a sustainable remedy. In both soils and humans, long-term reliance on supplements leads to decreased health over time.

Dr. Nunnally also drew a parallel between chemical herbicides like glyphosate and using antibiotics in people, explaining that both of those methods approach their problem with a “nuclear option” to address the issue from the top down; rather than building and maintaining a healthy environment from the bottom up. He explained how in both humans and in soil, the result of a “nuclear option” is often that only a few of the normal, healthy bacteria remain; creating an environment where pathogens are likely to dominate and multiply.

I also jotted down a few random helpful tidbits of information:

Betsy Ross shared her belief that if only 10% of the population learns these principles and adapts their behavior accordingly, that would be enough to tip the scales back in favor of natural balance. That’s what I call hope! I think this is an achievable goal. We might not get everyone involved in sustainable living, but I think we can muster up 10%.

Betsy also talked about how if the two “broken bridges” are repaired in an ecosystem, the plants in that ecosystem will take up to 80% of their nutrients from the healthy air around them. I guess there’s no need for synthetic 20-20-20 fertilizer if the plants get most of what they need for healthy production right from the atmosphere.

J.R. Builta shared some great thoughts about compost tea. He stressed the importance of brewing compost tea at ambient air temperatures. His point was that if you always brew indoors at 75 degrees, you will always get the same organisms that thrive at that temperature. But if you brew outdoors at ambient temperatures year-round, you will be more likely to grow a full spectrum of the organisms that thrive in different seasons at the full range of temperatures in your area. He also encouraged us all to be open-minded and innovative in brewing compost tea. He said, “Don’t be afraid to throw some different things in there and experiment.” I love that advice, and I think it’s a good policy. If we stick to one recipe and approach brewing as an “exact science,” we close ourselves off to learning about new possibilities, and we limit our potential for success.

Many thanks to J.R. Builta and Betsy Ross of Sustainable Growth Texas, and Dr. Stuart Nunnally of Nunnally and Freeman for taking the time to teach this free class on healthy soil and healthy humans. And thanks to The Natural Gardener for giving them a place to do it.

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  • Denise Anderstrom Douglass says:

    This is an excellent article on an excellent site! I subscribe to your newsletter. Keep up the great work!

  • Bonnie says:

    I absolutely love the article and especially the part on compost tea. What an education we get from this site!

  • Lucy says:

    Thank you – great article. I would also add that we need to stop tilling the soil as it seriously disrupts the work of the mycrorizae and microbes in the soil, as well as seriously impeding the ability of the soil to hold water. There’s a great video on You Tube showing the difference between tilled and not tilled soils – it convinced me! https://www.youtube.com/watch?v=q1aR5OLgcc0

  • Patricia says:

    Wow! Excellent information!

  • Don says:

    What do you think of aquaponic farming and nutritional balance so we are not getting all of the toxins that are in the soil?

    1. Michael Ford says:

      Hi Don – That’s a tough question. Regarding soil toxins – I think that soil can heal itself relatively quickly, and I’m very interested in the idea of bioremediation. All the more reason to apply compost tea and practice good soil management, I suppose. But there is obviously still a real concern for people living in heavily industrial areas, heavily agricultural areas, and/or near nuclear power, etc. I love the potential that aquaponics represents, and I have seen some really impressive systems in production. I have found good data about the size and yield of aquaponic plants, but I haven’t seen data about the nutritional value of aquaponic plants in terms of dietary minerals, etc. That’s what I’m really interested to see. Perhaps we can coax Leslie Parsons to weigh in on this – she’s been doing some very interesting research about soil toxins and remediation… Thanks – Michael

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