Being fairly new to the world of soil health, I’ve been introduced to a variety of interesting terms and sayings over the past year. Some of these words and adages were fairly self-explanatory… others sounded more like Greek to me. Of the latter, none were more perplexing than this head scratcher: “Mycorrhizae, superhighways of the soil.”
I have to be honest, outside of knowing that mycorrhizae was a fungus, the word meant nothing to me. Fortunately, one podcast from Radiolab not only familiarized me with the concept, but changed the entire way I view soil ecosystems.
The particular episode (“From Tree to Shining Tree”) outlines the role of fungi in natural systems and unequivocally reveals fungus to be one of the biggest contributing factors to plant growth. I strongly recommend anyone with an interest in ag give this episode a listen (34 minutes). While mainly highlighting mycorrhizae presence in the forest, the role of fungi has roots in virtually all natural systems and is highly applicable to the modern-day farmer.
Competition vs Collaboration
In agroecosystems, a common assumption is that plants essentially compete with one another to survive – if two species are grown together, one will dominate and one will wither away. However, as we’ve found throughout our search for truth at Merit or Myth, the most common assumptions are usually the ones that need to be challenged most.
No one knows this better than Dr. Suzanne Simard, a professor of forest ecology at the University of British Columbia. Over the past 30 plus years, Dr. Simard has put her skilled ear to the ground, listening for any and all truths that Mother Nature has to tell. One of those truths?
Plant life, and specifically that of trees, don’t really compete with each other much at all. In fact, they’re much more preoccupied with helping one another grow.
Conventional wisdom can’t make much sense of this. I struggle myself to understand it. After all, fellow trees, especially those of a different species, are often one of the biggest threats to individual survival. Dr. Simard’s findings clearly show, however, that not only are trees of the same species helping one another, but trees of differing species are the ones that do it the most!
NPR science correspondent and journalist Robert Krulwich has seen evidence of this first hand.
“Trees of totally different species were sharing their food underground. If you put food into one tree over here it would end up in another tree maybe 30 feet over there and then a 3rd tree over here and then a 4th… 5th 6th 7th… Turns out one tree was connected to 47 other trees all around it. It was like a huge network.”
One tree giving life to 47 others? How could this be possible?
“We were able to map the network,” Dr. Simard said, “And what we found was that the trees that were the biggest and the oldest were the most highly connected…. It’s just this incredible communications network that people had no idea about in the past because we didn’t know how to look.”
So okay, trees are more coworkers than they are rivals, but surely there’s more going on beneath the soil. After all, how are these trees, as Dr. Simard puts it, “communicating”?
The answer brings us full-circle: “Mycorrhizae, superhighways of the soil.”
Nature’s Most Misunderstood Contributor
Since most of us were old enough to carry around a textbook, we’ve been familiar with the idea of fungus… at least, we thought we were. Truth be told, even modern science’s understanding of this crucial organism has only recently begun to take shap.
“For a long time, they (fungi) were thought of as plants.” Jennifer Frazier, science writer for Scientific American highlights. “But now we know, after having looked at their DNA, that fungi are actually very closely related to animals. They’re one of our closest relatives actually.”
And it’s these fungi, the mycorrhizal fungi, that may be behind most plant life on earth.
Researchers have found evidence of a symbiotic relationship between fungi and plant life dating back to an estimated 400 million years. It’s this relationship and the fungi’s intricate network of tubes that allows tree roots to connect, communicate and share nutrients.
In fact, fungi is so crucial for plant life that some studies in natural systems have found up to 7 miles of active fungi in a mere pinch of healthy soil (are you kidding me?).
If anything has ever screamed in support of diversity and minimal disturbance, this is it!
So how do they do it?
Essentially, fungi have developed a two-pronged system for taking in nutrients. The first literally allows them to mine their way through soil, and even rocks themselves, secreting acid and drilling tiny holes in order to suck out nutrients. A large portion of these nutrients they don’t even use, delivering them straight to the surrounding plant life! But don’t get them wrong, fungi are not all cuddly altruists. The other system fungi have developed for nutrient extraction is a bit more… gruesome.
Despite their size, fungi are highly developed hunters – feeding on the carcasses of disregarded fish and live insects (specifically, springtails) that feed along the forest floor. Prior to their research, scientists believed that, if springtails and fungi were left alone, the insects would devour the fungi. To the researcher’s surprise, the opposite happened. The fungi found their way into the springtails and sucked out all of their nitrogen before depositing it into the nearby plant life. Stealing from the rich and giving to the poor… I’ve heard of that before.
So what do the fungi get out of it? In exchange for their tireless service, they are supplied with carbon (one of the key building blocks of life) from the surrounding plant life.
Research shows that some trees give anywhere between 20% to 80% of their carbon directly to their fungi friends.
BACK TO THE FARM
So how does this apply specifically to a farming operation? Well, input costs have been a major theme we’ve touched on over the past couple of months. As we all know, profitable crops rely heavily on adequate supplies of nitrogen, phosphorous, potassium and so on. What researchers like Dr. Simard are revealing, however, is that healthy soils and mycorrhizal fungi naturally supply these minerals and nutrients on their own.
The bottom line? Life below ground is as abundant and complex as the life above it!
When you look at it through this lens, it’s no wonder why input costs have risen so high. Practices like tillage rip up the soil, the fungus, and the very nutrients that supply life. Without healthy fungus and natural soils, nutrients need to be artificially plugged in in order to ensure profitable yields.
On the other hand, the usage of no-till (minimal disturbance) and cover crops (enhanced diversity), over time, lead to an increase in fungi and, thus, soil biomass, on their own. This is just the way nature intended! In fact, when left alone, as science journalist Jennifer Frazier says, “It’s almost as if the forest is acting as an organism itself.”
If the rest of nature can work together for the greater good (even those species conventionally thought to be competitors), can we figure out ways of working alongside rather than against nature? One of our goals at Merit or Myth is to create a community that fosters conversation and community growth. Just like the trees in the forest, we’re much stronger together than we are separate. Just as we’re learning along our journey, crops are much stronger when filled with diversity than monocultures. What knowledge do you have that can help your fellow farmers thrive? Odds are, just like it is in nature, they’ve got a few things they’ll send your way as well.
Join the Revolution,
– Barrett
SOURCE: http://www.radiolab.org/story/from-tree-to-shining-tree/