Most of us have never thought about what is actually happening beneath the surface when a forest thrives without any help from us. The answer is in the soil — and it changes everything.
Healthy soil is not dirt. It is a living ecosystem, and plants are at the center of it. Through photosynthesis, plants convert sunlight and CO₂ into sugar — and they send the majority of that sugar down to the microscopic organisms living around their roots. In exchange, those organisms provide the plant with nearly everything else it needs: minerals, nutrients, water during drought, protection from disease.
Synthetic fertilizer breaks this partnership. When nutrients are delivered directly, plants stop feeding their microbial networks. The underground community collapses. The plant becomes dependent — and vulnerable. It is one of the hidden costs of industrial agriculture, and it shows up in depleted soils, weaker crops, and rising inputs year after year.
There is another way. The Johnson-Su bioreactor — developed by soil scientists David Johnson and Hui-Chun Su Johnson at New Mexico State University — is a simple composting system that produces a living inoculant rich enough to begin rebuilding what synthetic inputs have destroyed. One tote. Twelve to eighteen months. And the microbes do the rest.
What is a Johnson-Su bioreactor?
A Johnson-Su bioreactor is a low-tech composting system built to stay aerobic — meaning it is never turned, never heats up, and never kills the fungal networks it is growing. Unlike standard compost, which after four weeks contains around 23 microbial species, a bioreactor left undisturbed for a full year develops 99 prevailing species. That community is rich enough to communicate and coordinate in ways simpler compost cannot.
What you end up with is not compost. It is a living inoculant — a teaspoon of which contains more organisms than there are people on Earth. Applied to soil or plant roots, it begins rebuilding the microbial networks that make plants resilient, self-sufficient, and genuinely productive.
The science of why it works
Bio4Climate first brought this research to our community in 2017, when David Johnson presented at our Climate Reckoning conference at Harvard University. His long-term field trials showed that a single application of bioreactor inoculant produced five times the biomass in the first year — and after seven years, with nothing added but a new cover crop each season, 22 times the biomass of the control. No additional inputs. Just living soil doing what it evolved to do.
His research also found that the inoculant unlocks phosphorus already locked in agricultural soils — meaning large farms using this system are running on zero added phosphorus, because the microbes do the work instead.
I refused to call it compost because it’s so much more than compost. It’s inoculant.
Shar O’Brien, Soil Thrive Hawaii