A Burgioning Revolution: Agriculture Needs Focus on Soil Health
Geology without biology is dirt. Put the latter to the former, add a focus on building for the future, and you have a system of geology and biology to make soil. You may even have the makings to sustain humanity for generations to come.
That’s the easy way to explain Dr. David Montgomery’s presentation to the Maximum Farming Club Conference attendees in January. The path humanity has taken to make so much dirt of its soil and what it will take to spark agriculture’s potential next revolution is more complex. It is, however, he believes, a doable goal if agriculture is willing to change.
That is why society must pay attention to the loss of productive soils, put focus on restoring what is there, and getting the most out of what soils have to offer. At times, it was like listening to a tutorial on the Maximum Farming System.
Montgomery used his trilogy of books, “Dirt”, “Growing a Revolution”, and the book he co-wrote with his wife, Ann Biklé, “The Hidden Half of Nature” as the basis for his presentation. Soils are a strategic resource for mankind, Montgomery says. While most people think of things like oil and energy for strategic reserves, soil may be the most important, and probably the most under-appreciated crisis in terms of soil degradation.
“If we think about what makes healthy soil, it’s the mix of geology and biology,” Montgomery says. “It’s the marriage of those two; the interface between the dead world of geology and the living world of biology.”
Loss of Productive Soils
Soils are responsible for 97% of our food, either directly through plant food, or indirectly through proteins, he says. The other 3% coming from the oceans. That makes the preservation of soils essential to the long-term sustainability of human kind.
Cornell University scientist David Pimental, according to Montgomery, discovered in 1995 that one-third of the world’s productive soils had been taken out of agriculture production since the end of WWII; an area the size of China and India combined.
While the degradation rate has slowed, the current pace is that we’ll see one-third of productive farmland go away by the end of this century; daunting figures for a planet that must feed an additional 2 billion people in the next 30 years.
Restoring Soil Health
Montgomery’s research shows worldwide soil conditions in peril where every region of every continent has a majority of soils severely degrading. Conventional farming is the culprit, he says and should be society’s biggest concern.
“How fast the continents have eroded for the last 100,000,000 years or so…those are all about a percent or two of a millimeter a year. That’s 100 times slower than rates of conventional erosion off plowed fields as a global average. That’s the problem.”
The table also shows the solution, in Montgomery’s mind, and that is a conversion to more conversation about tillage and specifically no-till. Then comes the focus on rebuilding soil structure.
Through his research, he visited with farmers all over the world, including the United States and Africa. But the idea was sparked by the restoration of his own yard in north Seattle, Washington.
“You know, we basically had an old growth lawn and, when we stripped that lawn off,” he says. “We found that we had glacial till— we had dirt. There wasn’t a single worm living in there. There was no microscopic life visible at all.”
Fast forward four years and they have about two inches of new top soil. “Nature doesn’t do it that fast, but we can.”
This brings the discussion to how we apply an understanding of soil ecology and the quest to build soil, not just in their yard, but across all regions where soil degradation is happening.
“I think this new revolution can be rooted in the idea of thinking differently about the land,” he says. “It’s not so much about the specific tools we might use to get there.
“We can use all flavors of technology and conventional wisdom, but we need to view them through the lens of does it help the health and fertility of the soil as our metric.”
Feed the Soil
“We started to notice the order in which life came back to our yard; microbes, visible fungi, arachnids (spiders), worms and amphibians, reptiles and birds. It mimicked the order in which life evolved on earth.”
That told Montgomery a lot about how ecosystems are built in soils. It’s from the bottom up, as in the root systems. Then it becomes about the parts we can see, and that is why we focus so much on season-long root development with the Maximum Farming System.
Montgomery and Biklé began looking at the processes taking place. They placed organic matter on the soil surface and in six months, it was gone, he says. “Anne said, ‘well, the soil was hungry.’ So we kept feeding it.”
They were adding compost to the soil surface and the microbes were breaking it down. Then it was further broken down by bacteria and fungi, which are, in turn, eaten by soil organisms. When those organisms are eaten, the waste is excreted as nutrient-rich food for the soil. They were essentially “little bags of fertilizer.”
“They were turning organic matter, which has in it the mineral micro nutrients that are essential for growing plants, because they used to be plants. And they’re recycling that material and turning it into forms that new plants can actually take back up once it passes out the back end of that soil life. It is much more soluble and plant-available than it was when it was leaf.”
Two Way Street
While it’s clear how the soil feeds plants with microorganisms, there’s also another half of the story…the root systems.
“We were trained in grad school to think of the roots as a plant’s straws that brought nutrients out of the soil and suck up water that had soluble nutrients in it. But it turns out that’s only half the story,” Montgomery says.
There are root exudates, and these push food, proteins, sugar and fats, out the root tips and essentially feed the soil, which, in turn, feeds the plant’s root system. It’s a give and take relationship that is mutually beneficial. Montgomery refers to it as an underground economy.
“The rhizosphere extends about one millimeter to one centimeter around every root hair on most plants. That rhizosphere is a zone full of bacteria and fungi. If you want to find some of the most life-dense areas on this planet, look around the roots of a healthy plant. Those plants, with the exudates they’re pushing out of their roots, are basically setting a buffet in the soil and life comes to that plant.
“Those exudates get only about one millimeter to one centimeter away from those root hairs before something consumes them. And what happens when those things get consumed by an organism? Well, it gets metabolized and it gets transformed into metabolites, which is the polite word for waste products.
“So the plants are pushing food out into the soil. The microbes are consuming them, then the microbial manure that comes out is actually kind of interesting. It’s not just simply elements, they’re elements put together in a way that benefit the plant. You’ve got these micro bacteria in a completely different family of life producing a hormone that makes that other organism healthy. But then the other organism when it’s healthy and it leafs out, it captures more solar energy that is putting more energy back into the soil to feed the microbes. That’s a virtual circle.”