Most people—as I did for over 30 years—overlook the importance of grass. It has been relegated by modern society to suburban lawns, soccer fields, golf courses, and strip mall embankments. Though our modern ways too often prevent grass from doing so, this unassuming little plant plays a vital role in the management of the earth's carbon cycle—the reason we have air, food, and water. Simply put, if we hope to grab a hold of runaway climate change and continue to live on a habitable planet...we must not overlook the grass. In fact, that "miracle ally" in the fight against climate change that we're all waiting for...might be right under our feet.
OK. Now that the compelling introduction is out of the way...let's get down to business.
According to the World Resource Institute, grasslands cover 40.5% of the terrestrial earth (that is, the planet's land mass if we exclude the permanently-frozen climates in Greenland and Antarctica). That's over 20 million square miles...of grass. Clearly, anything covering that much of the earth is a force to be reckoned with. And so, if we're wrestling with questions concerning the global climate shouldn't we fully understand the evolution and workings of one of the globe's biggest forces?
The Evolution and Life of Grass
A herd of buffalo in Katavi National Park in Tanzania.
Once upon a time, the planet's grasslands were roamed by wild and abundant packs of herbivores—buffalo, bison, horses, sheep, elephants, and so on. For protection from the also-wild-and-abundant predators, herbivores would group themselves together in tightly-bunched packs. These packs would move into an area of grassland, eat, trample, defecate, and move on—not returning to the same particular spot for maybe a year or more. This mob-grazing action left the grassland's soil covered, protected, and well-supplied with organic matter—perfect conditions for building soil and growing more grass while the animals were away. The grass was managed by the grazers.
This "grazer/grazee" relationship started with the arrival of the herbivores, which Wikipedia tells me was during the Mesozoic Era—220 million years ago. It ended (roughly) about 100 years ago with the arrival of industrial agriculture—ranching, highways, fences, CAFOs, etc. And, just to play it safe and to cut down on the amount of backlash I'm sure to receive, let's say it ended 200 years ago, since we have definitive accounts from the Lewis and Clark expedition that large packs of wild buffalo—with 20,000 animals or more—were still roaming the American grasslands in 1805.
We're building soil on some land degraded by overgrazing. On the left is before the sheep eat their hay breakfast. On the right is just after.
So, for roughly 219,999,800 years, herbivores inhabited the grasslands. During that time, the herbivores changed, adapted, and evolved from their Mesozoic forms to their modern forms. Of course, as the herbivores evolved, so did the grasses. Grass species that were able to thrive in the conditions created by the herbivores, did...and reproduced. Grass species that suffered in the mob-grazing conditions created by the herbivores, died. So what we're left with today are grasses that have evolved—over 220 million years—to thrive when paired with massive packs of roaming herbivores.
The grasses and grazers are two parts of one system.
But! We've taken the herbivores off the land. Through mismanagement, through misguided attempts to preserve the grasslands, through the industrialization of meat production, through the expansion of human societies, through the expansion of cultivated land—we've removed the roaming packs of herbivores from the grasslands. So, the grasses that evolved to thrive when mob-grazed by herbivores, are no longer thriving. Grasslands are dying off and deserts are growing instead.
So to understand why this broken "grazer/grazee" relationship matters for the climate and for humans, we'll have to look more closely at the nature of grass itself. Let's start with...
What Is Grass...Really...?
Four hundred years ago a Dutch scientist named Jan Baptist van Helmont (sorta) discovered that plants are almost entirely atmospheric carbon. Gas. Plants are gas. That's true.
The experiment was simple. van Baptist weighed a pot of soil. He then weighed an unplanted willow sapling. He planted the willow sapling into the pot of soil and added nothing to the pot but water. After five years, van Helmont removed the young willow tree from the pot—roots and all—and again weighed the willow and the pot of soil. Over those five years, the tree's mass had increased from 5 pounds to 164 pounds. The mass of the pot of soil had decreased from 200 pounds to 199 pounds and 14 ounces—a loss of only 2 ounces.
Now, van Helmont was working a century before the discovery of carbon dioxide, so I think he can be forgiven for incorrectly concluding that the near-entirety of a plant's mass came from water. Of course, we now know about carbon dioxide and photosynthesis. Had van Helmont kiln-dried the tree, thereby removing all the water, he would have been left with a weight that represented only what the tree had taken in as carbon dioxide gas in the atmosphere.
As anyone who has handled a load of kiln-dried lumber—or wagons full of dried bales of hay, for that matter, as we do—carbon attained from the atmosphere is a significant percentage of a plant's mass. (I've heard 95%. I've heard 65%. I'm unsure of the exact percentage in grass, but it is certainly "most." It is sacrilegious for a hay farmer to bale wet grass, but I might this summer to compare weights. I've done weirder things in the name of science.)
So if grass is mostly atmospheric carbon, it is important to know how and when grass collects that carbon from the atmosphere.
How Grass Grows
Grass grows at varying rates of speed throughout its life cycle. It grows slowly at first as it struggles to put down its roots and build the first sprouts of leaf. Then, at a point—when it has enough root in the soil collecting water and enough leaf in the sun collecting energy—the plant's growth explodes. In this stage, the plant draws in carbon dioxide at its fastest rate—using the carbon to build more leaf and more roots, and releasing the oxygen.
When the plant is strong enough, energy is diverted away from creating biomass to creating seeds. Growth slows.
The growth, over the life of the plant, can be graphed as a sigmoid curve.
It is the lightning-fast middle stage of growth—as the grass is creating most of its mass—that is most important to understand. During that stage, the plant uses the carbon to produce deep roots and a tall, lush, green, leaf that blows in the wind and calls out to any hungry herbivores. The herbivores see the grass leaf, graze it down, and move on.
In response to losing so much leaf, the grass plant sloughs off some of its root. Grass likes to maintain a 1:1 ratio of leaf to root. (Correction: Grass does not slough root. See here.) This "grazing and sloughing" resets the grass plant back to the beginning of its rapid growth stage—and it shoots right back up again—drinking in a bunch more atmospheric carbon and sequestering it into the soil as root matter and, indirectly, manure.
It would be more accurate to say that plants "inflate" from the atmosphere, rather than "grow" from the ground. And, when the gas they draw in passes through their leaves, it becomes a solid—wood, root, sugars, etc.
Well-managed grazers by well-informed graziers can keep a field of grasses in a near-constant state of rapid growth throughout the growing season. This optimizes the carbon-sequestration and soil-building action of the land. Grasslands that are poorly-managed (with over-grazing or over-resting) degrade the soil and eventually turn to carbon-emitting desert.
A Better Approach
On our farm, we have grass because we have herbivores—and we have herbivores because we have grass. Land owners and managers around the globe need to understand the evolutionary relationship between grass and grazers. When herbivores are removed from the grasslands, both suffer. And, since we tend to eat the herbivores we've removed from the grass, we suffer from eating animals kept in unnatural environments (concrete slabs) and fed unnatural diets (corn and far worse). With proper management of packs of grazing herbivores, grasslands that have turned into desert can be turn be turned back into grasslands—all while improving the lives and health of the animals and, therefore, our own food.
Same soil. Year over year progression of our transition from pesticides & corn to managed grazing.
Our farm has been a hay farm for nearly 80 years. As grass farmers, our tools (...more like teammates...) are sheep, chickens, turkeys, pigs, and management. We use no chemicals, nor chemical fertilizers—not only because it saves us money, but because we don't see how we could recreate the natural environments under which grass evolved to thrive without using natural tools. The meat we sell is a byproduct of our grass operation.
During our top years, we have been able to produce 10,000 35-pound bales of dried hay on our 50 acres. Given what van Helmont taught us 400 years ago about the source of a plant's mass, that hay is actually 175 tons of atmospheric carbon we've sequestered. We feed that carbon to our sheep and they turn it into meat, sheepskins, waste, soil—and many other things that will never oxidize back into the atmosphere. Atmospheric carbon is a free and abundant raw material that just wafts across our farm. We use the grass to grab it and turn it into high-value products. For much of what we sell, the only input we need is sunlight.
Hope in the Face of Climate Change
The amount of carbon we sequester on our farm doesn't amount spit in the ocean in terms of the global problem. But, the regenerative agricultural practices we follow, if they caught on, could have a global impact, and quickly. There is no more nor less carbon on Earth than ever there was. It's just above our heads heating the planet instead of below our feet feeding the soil. Grass and grass farmers—with much larger tracts of land than ours—can get to work today putting the carbon back underground, while producing food, fuel, and fiber. (And, of course, managed grazing is just one regenerative method. There are many. We'll cover the awesome power of silvopasture in another post.)
But, imagine for a moment if the next generation of farmers, land managers, and policy-makers viewed the excess atmospheric carbon as an economic opportunity instead of a crisis—an opportunity to grow and sell high-quality food, to provide land restoration services, to grow and sell fuel, to grow and sell all-natural and regenerative clothing and bags and hats and gloves and slippers and so on. Then, we'd have a gold rush on atmospheric carbon, followed by an investment boom, followed by a crisis of too little carbon in the atmosphere....
I'll leave you with this food for thought: there are 96,000,000 acres in the US alone devoted to corn. (That's only 1,920,000 times larger than we are.) Imagine if we—as an evolving species ourselves—were clever enough to let the cows out of the CAFOs, and allowed them to graze the fields...that currently grow the corn...that's trucked to CAFOs...to feed the cows. We'd have beef and dairy industries that rebuilt soil, improved the nutritional value of our food, combated climate change, reduced our dependence on fossil fuels, eliminated the need for antibiotics in meat and milk, and significantly improved the lives of the cows. I, for one, would rather we did that.
Correction: The popular theory that grass adds organic matter to the soil by sloughing off root when grazed is not correct. This was pointed out to me on this post our Facebook page by Sean Kettle, and backed up in the comments by Dr. Elaine Ingham—a leader in the soil movement. It's a blessing to have such good teachers.