Quorum sensing and it’s impact on your soil health: Plant diversity is the key

By Matt Reese

OCJ publisher Bart Johnson once asked the staff during an office lunch: if you could only drink one thing for the rest of your life what would it be? His answer: root beer. I think mine would be water. This led to a long debate of the merits of root beer versus water.

The discussion then turned to food. I think I could eat pizza just about every day. I am guessing that most of you (other than Dale Minyo who really does not care for pizza) may feel the same way. Now, if you just had one pizza ingredient to eat every day, what would that be? For me I think it would have to be the cheese (it is dairy month, after all).

Christine Jones, who served as the keynote speaker at this spring’s Conservation Tillage Conference in Ada, is a retired soil ecologist from the University of New England in Australia. She wants people to start thinking about feeding their soils in a similar way.

“Imagine you have cheese for breakfast, cheese for lunch and cheese for dinner and that is all you have 365 days a year. Even if that cheese happened to have all of the nutrients in it that you needed, you would still have a very simplified gut micro biome and that means that certain genes in your body that are activated by your gut microbes would get switched off. You wouldn’t be able to protect yourself from diseases and you could get some kind of autoimmune disorder. Then you’d find yourself in a situation where you start taking other kinds of drugs, supplements or antibiotics to deal with whatever the issue is because your gut flora can no longer maintain your health,” Jones said. “We think we are so clever and we’re so highly evolved and the masters of our fate, but it is actually the microbes in our gut that control our health. You feed your gut and the gut flora look after you. This happens in our soils too.”

Life on earth would not be possible without skajillions of microbes and fungi we never see and take for granted every day. They live all around us, inside us and they are a vital component to agriculture in ways we are just starting to understand.

“All plants are embedded in a microbial world and we also have a microbial world embedded within us. Microbes are capable of performing many amazing tasks. There is no such thing as an independent organism. All species need other species to survive. We need to support the soil micro biome so that it will look after the plants and we won’t need to use fungicides, fertilizers and insecticides. The soil micro biome has become so simplified through monoculture, just like if you only ate cheese every day,” Jones said. “There is nothing wrong with cheese as part of a diverse diet and there is nothing wrong with corn and soy as part of a diverse crop rotation.”

Plant diversity supports soil microbial diversity.

“The presence of green plants is the single most important factor for soil health but it not enough to simply have green plants. A simple system is a degraded system. If it does not have diversity, it is not going to function effectively,” she said. “Native American prairies have 500 to 700 plant species with 60% forbs and 40% grasses. Diverse plant communities support diverse soil micro biomes. The more diversity you have the more possibility you have.”

Like a board of directors needs a quorum present to make decisions, microbes need a similar situation to initiate their species-specific behaviors.

“In the microbial world, quorum refers to density dependent behavior that regulates gene expression in the microbial community. If they don’t have a quorum they can’t do their work,” she said. “They use quorum sensing to collectively coordinate behavior and achieve certain outcomes. Microbes can’t see or hear or speak, but they communicate with each other extremely well and they are incredibly well organized. This occurs in bacteria, archaea, fungi, and viruses.

“You are much bigger than a virus and you could overcome it very easily, but they are under the radar. They sit in your body and multiply very rapidly. When they reach a quorum and detect there are enough of them there to overpower you, they switch on their virulence genes on. That is how pathogens invade our bodies. They use a chemical signal called an auto inducer. They also know how many others there are. Our bodies work that way too. All of those chemical signals are happening in our bodies and we know very well what happens when that signaling system gets disrupted by a virus. The same things happen in our soils. The signaling systems are getting disrupted all the time by how we manage agricultural soils. The soil biome needs to behave as a coordinated system. If we eliminate plants above ground we eliminate the life below ground. That is why a monoculture is really unhelpful for the soil.”

It is easy to see why Jones’ presentation was a full house this spring and why I’m now in the mood for pizza with all the toppings — and maybe a root beer.

For more from Jones, visit https://www.youtube.com/watch?v=K8_i1EzR5U8 and Amazingcarbon.com.