The Protein Problem
I grew up in what used to be the rural South of the US; now the suburban South. In the Spring, I would help my mother plant tomatoes; after the danger of last frost had passed. I’d dig a hole, and she would put a small tablespoon of fertilizer in each hole. Seeing the tiny pebbles of granular fertilizer, i asked her what the stuff was, and she furnished some cryptic Southern euphemism like “TLC” or “good stuff.” She would instruct me to incorporate the fertilizer, and I would work it in by breaking apart the cool, friable soil with my fingers. We would then place a small seedling in each hole; burying the stem all the way up to the first true leaves.
One day, my mother came home and made an exciting announcement. She said, “Look, we finally have organic produce at our grocery store!” Beaming with pride, she held up a shiny, green Granny Smith apple. In response to this, I did what everybody does the first time they hear about organic food. I said, “So what? It doesn’t look any different than the apples you usually buy. What makes it organic?
Her response was horrifying. “Well, organic means that the food was grown without being treated with herbicides, pesticides, fungicides, antibiotics, hormones, and inorganic fertilizers.” To which I replied, “So that’s what you’ve been feeding us?!”
I promptly developed a fascination with agriculture, and all the different methodologies and cultivation practices related to the panoply of crops that make up the human diet. The next Spring, I asked my mother if the fertilizer we used in the garden was organic. To my dismay, she said that it wasn’t. I asked if we could fertilize the garden organically, and she capitulated; albeit, somewhat begrudgingly. I would soon understand the reason for her hesitation.
So, we set about soliciting a nearby cattle farmer for a bit of rotted manure. My mother instructed me to load the back of our pickup with shovel-full after shover-full of the black crumbly material, and when we returned home to apply it to the garden, I was shocked at just how much manure each plant required as an equivalent measure of fertility; compared with the granular synthetic fertilizer we had used before. I kept asking “Is this enough?” and with each shovel-full my mother would respond, “Keep going…”
The monumental conversion factor of organic manure to inorganic fertilizer was unsettling to me. It didn’t compute. Why should the nutrients in one form of fertilizer be locked in a package with orders of magnitude less mass than another? It felt like choosing between two multi-vitamins, where one was the size of a normal pill, and the other was the size of cinder block. It didn’t make sense, so I set out to figure out why.
In order to understand the vast disparity of nitrogen concentrations between the two fertilizers, I began researching the various ways organic matter is synthesized. The vast majority of trees, grasses, even seaweed are simply recipes of carbon that have been synthesized into organic forms of structural living tissues through the process of photosynthesis. Most are polysaccharides like the cellulose in wood and grass, however a relatively minuscule amount of living tissues are proteins; a type of organic molecule containing nitrogen that mammals need to ingest frequently in order to survive. These tend to be more concentrated in the seeds of plants, especially legumes (beans), as well as animal tissues.
The granular fertilizer my mother used was accordingly branded “Miracle-Gro” (see label below). A cursory investigation of the label revealed nitrogen as the most abundant ingredient, and I read on to see what the source of it was. It turns out that the material supplying the element nitrogen to the concoction is a chemical called Urea.
The Haber-Bosch Process
Urea is produced on an industrial scale from ammonium through the Haber-Bosch Process. Natural gas, a fossil fuel, is the principal source of energy that powers the process.
The process directly synthesizes ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) gases. Natural gas is primarily used as a source of hydrogen and as a fuel for the process. Urea is then synthesized in a separate process from ammonia and carbon dioxide (CO₂). Ammonia produced in the Haber-Bosch process is the precursor for the near totality of inorganic fertilizers used in conventional agriculture, and the vast majority of croplands are cultivated conventionally using these inputs.
The miraculous feature of this process is that it enables nitrogen to be packaged without the bulky carbonaceous components associated with the heavy fiber load of plant tissues; abundantly present in organic sources of carbon like cover crops and herbivorous manures. This is why a few spoon-fulls of Mother’s granular fertilizer was so much less cumbersome than the comparatively monumental equivalent of rotted manure. Nitrogen that is organically bonded with carbon is loaded down with a lot of extra mass; compared to the nitrogen being delivered through urea.
The Protein Element
What is so special about nitrogen? It turns out a lot. Every single amino acid contains nitrogen, and amino acids are the building blocks of proteins. Put another way, every living tissue and metabolic pathway in your body is made of and dependent on proteins.
How essential are proteins? Because living cells require nitrogen to synthesize proteins, and nearly all biological function requires proteins, nitrogen is absolutely vital. How vital? Humans can live for approximately 70 days without consuming proteins. You can be vegan, vegetarian, Paleo, Whole 30, anything you want; as long as you have protein, or you die. It’s that simple.
So, humans need protein to survive. Humanity is getting sufficient protein from agriculture, but farms are obtaining nitrogen for protein production from super highly concentrated inorganic fertilizer derived from mining via the Haber-Bosch process.
This begs an obvious question. What happens when it runs out?
Before we tackle that problem, let’s look at how we got here.
Third Agricultural Revolution
Our civilization is currently in the Third Agricultural Revolution. The first was the Neolithic Revolution over 10k years ago, in which wild plants were domesticated and permanent agrarian settlements were built.
The second was the British Agricultural Revolution, which began in the 17th century, and it was marked by the employment of crop rotations, exclusive land ownership rights, and heightened labor coordination.
The current epoch has been dubbed The Green Revolution, which began a century ago, and is principally characterized by the global scale distribution of fertilizers derived from geologic rather than organic means; that is, the use of inorganic fertilizers.
So, what’s the difference between organic and inorganic fertilizers? This is where Mother’s Miracle-Gro comes back into the picture.
For millennia, farmers have relied on legumes to deposit atmospheric nitrogen in the soil, and this has been accomplished by planting one cover crop for each cash crop harvested; replacing the nutrients from the harvest of a cash crop by committing a cover crop full of nutrients to the soil; feeding the soil dwelling microorganisms and loading the soil strata with surplus nutrients. Nodules on the roots of legumes fix atmospheric nitrogen in the soil; making it available to plants. However, legumes require an entire growing season to fix enough nitrogen in the soil to grow a cash crop with adequate fertility the following growing season.
In stark contrast to the relatively slow way that legumes fertilize soil, the abundance of nutrients supplied by inorganic fertilizers in which the cumbersome carbon has been removed, has allowed modern agriculture to produce crops every season. Conventional 3-crop rotations, including maize, wheat, and soybeans, are now accomplished in 2 years, whereas it takes organic production 5 years to produce the same yield; one growing season for each cash crop, and one for each cover crop to replace the nutrients that were harvested for consumption (plus winter dormancy).
As the Haber-Bosch process has made nitrogen readily available without the temporal limitations required for legumes and animals to organically restore nutrients over the course of a growing season, the Green Revolution increased yields in the developed world by 900% in less than a century (see chart below).
The catch is that, because of the tremendous increase in crop yields that inorganic fertilizers have enabled, the scale of industrial agriculture has not increased proportionally with population growth (see chart below). In half a century, the number of acres in cultivation per capita has been reduced by >50%.
Therefore, if average crop yields remained at pre-industrial levels, the crop harvested in the year 2000 would have required nearly four times more land than is currently in cultivation; an area encompassing nearly half of all ice-free continents. This is compared to <15% of the total land area being cultivated at present.
Malthusian Trap
Thomas Robert Malthus described in his 1798 book, An Essay on the Principle of Population, that population growth is exponential, whereas increases in food supplies are linear. A culture’s ability to invest in new agricultural resources and cultivate more land cannot mathematically keep up with increases in population.
So, populations ebb and flow. The Lotka-Volterra equations demonstrate that predator and prey populations are beholden to each other. The more the prey population is consumed by the predator population, the less available that food supply will be to the predators; thus, in turn, decreasing the predator population. This is also true for humans and the resources we need to survive, like proteins.
So, how has humanity maintained sufficient caloric supplies during the greatest population increase in the history of civilization? Simple: we broke the speed limit; or the nitrogen limit more precisely.
Rather than scaling organic agricultural assets with population growth, we have transitioned to an inorganic means of fertility to make up for the incredible increase in caloric demand.
The problem is that inorganic fertilizers bypass the natural limitations of nutrient transfer that are intrinsic to healthy ecosystems. The ecosystem doesn’t have to “make” the fertilizer through the breakdown of organic matter. It just, quite literally, falls from the sky. Our technological capacity to bypass this biological limitation has allowed us to increase yield without scaling cropland area. However, with over 5 billion people dependent on inorganic fertilizers produced using fossil fuels, we no longer have the capacity to transition from inorganic back to organic cultivation. The enormous loss of yield would create a famine of global proportion.
The Future
The human population of Earth has increased by nearly 500% in a century (see chart below), and this historically unprecedented increase coincides precisely with the widespread application of inorganic fertilizers; consistent with the Third Agricultural Revolution.
Humanity has nourished a civilization of 8 billion people with a food supply that is fatally dependent on non-renewable resources. It took the Earth 300 million years to fossilize the remnants of living tissues into the fuels that are burned to organize atmospheric nitrogen into the soluble fertilizers that power our food supply, and humanity has consumed an enormous portion of this supply in the span of a single century.
The entire food system is beholden to humanity’s collective ability to cooperate rationally to uphold a finite fossil fuel supply chain that has been strained for decades by global conflict.
Green ammonia, which is synthesized through the process of electrolysis rather than through the burning of natural gas, presents an approach requiring little to no fossil fuels. Though the prospect of creating green ammonia using nuclear power contemplates a near limitless supply of urea, it does not take into account the vast increases in arable cropland needed to deploy this fertilizer to maintain sufficient yield to sustain a growing population. We simply don’t have the area to meaningfully increase crop production.
More importantly, the second order effects of scaling up agriculture are vastly more challenging. We don’t know what happens when the spectrum of species is narrowed through the conversion of healthy biodiverse ecosystems to cash crop monocultures. The Industrial Revolution has already heralded the greatest loss of biodiversity since the extinction of the dinosaurs, and further disruption of ecosystems through conventional agriculture would exacerbate the current mass extinction.
If human beings intend to be viable tenants of Earth in a post-inorganic world, we are going to have to wean our culture off of inorganic fertilizers and transition to serving biologically functional roles in diverse, healthy ecosystems. A simple step in the right direction is to introduce yourself to a local cattle farmer, and see if they need rid of some rotted manure this season.
