John Kempf argues that single- or few-species microbial inoculants can be beneficial because certain 'keystone' or pioneering microbes (e.g., Rhizobium, mycorrhizal fungi, Trichoderma, Bacillus subtilis) can restructure soil microbiomes and attract broader microbial communities. He emphasizes applying inoculants near living roots (e.g., as seed treatments) to allow root exudates to support establishment, and cites Rhizobium-style nitrogen fixation as a precedent — expecting colonization and nitrogen fixation within roughly 30–45 days. He names Biocoat Gold as an example seed-treatment inoculant.
Questions this video answers
January 31, 2025.
Within 30 to 45 days after planting.
Biocoat Gold.
Chapters
Why would we consider single species microbial inoculants beneficial? Or broadening that from a single species? Sometimes you might have microbial inoculants that have two or three dozen species. When we know that we have a soil microbiome that has tens of thousands of species that are currently identified with conceivably millions that we haven't even identified yet, there's this recurring question, how do we consider that it's possible to add a microbial inoculant that only has a handful of species and expect them to establish a viable population and expect them to make a difference? There is this concept in biological systems and ecosystems of what are termed keystone species. I think of them in the microbiome context as being pioneering species where you have a couple of species that when they are present, they change the behavior of everything else that's present in that ecosystem. And so, from a soil microbiome perspective, some of my friends have been telling me they've been having a lot of fun with this concept. I mentioned it once in a podcast, just in passing. I talked about the idea of having a pool party if you want to have an awesome pool party with 200 people showing up. By the way, I've never thrown a pool party, so I have no idea what I'm talking about. But if you want to have an awesome pool party with 200 people, it's not a question of needing to invite 200 people. The question is, who are the 10 people that you need to invite so that the other 200 people show up? Who are the cool kids that everyone wants to hang out with and that are attractive, and the remaining 200 show up? I think similarly about these keystone species, where you can have a small group, you can have five or ten species or groups of species that create an environment where everyone else wants to show up. Mycorrhizal fungi is one example of what can be a single species inoculant that completely changes the ecosystem. We know the same is true of Trichoderma. The reality is, I'm puzzled by this objection to using inoculants that only have a few species, because the reality is we've been using rhizobium bacteria inoculants for decades, where we are inoculating a single species of a microbe onto legumes so that they colonize the legume root system, produce nodules, and effectively fix nitrogen. And let's just expand that concept to be a bit broader, to not just be rhizobium, but also to include mycorrhizal fungi to include Bacillus subtilis, to include a larger group of these pioneering keystone type microbial species that change the environment. So now this comes to the second, leads us to the second question is how do we expect to add one microbe into this mix into the pool and expect that microbe to establish a viable population and shift the rest of the microbiome? From what I've been able to observe, the greatest success occurs when we introduce a microbial inoculant similar to the Rhizobium in proximity to a living root system. When we just go out there and spray them on dead bare soil, let's say in an almond orchard or something like that, where we have no living root systems, they're going to struggle to survive. But if we apply them, when there are living roots present and those roots begin releasing root exudates and photosynthesis and feeding those microbial inoculants that we've added, then they have a serious shot at establishing a viable population and completely changing that microbiome architecture and the group of microorganisms that are there and the collaborative relationship they have. This is the foundation that is required in order to have the Rhizo Fiji cycle working and to deliver abundant nitrogen from our soil. We should think about inoculating our corn crops. And all of our crops, not just legumes, but all of our crops, should be inoculated with microbes that colonize the microbiome, that fix nitrogen, that deliver nitrogen to the crop, and not just nitrogen, but other elements as well. This is how you deliver nutrients in a biological system. And this is the reason for being, this is the foundation of why we, we use our microbial inoculants like Biocode Gold as seed treatments so that we have them there present by the seed, just like a Rhizobium inoculant, to deliver nutrition to the crop in the first growing season. Rhizobium fixes nitrogen immediately. We have the expectation that we'll have successful colonization and nitrogen fixation within 30 to 45 days after planting. The same should be true of any other seed treatment microbial inoculant like Biocoat Gold. We should expect it to colonize and begin delivering results right away.
