[Note: The following is a significant expansion of the soil nutrients discussion of Sample 44.]
SOIL
NUTRIENTS
All life depends, directly or indirectly, on essentials like
sunlight, water, oxygen, carbon dioxide, nitrogen, phosphorus, potassium, soil,
and so on. In healthy wild ecosystems,
these essentials are not depleted. The
magic of evolution nurtures their ability to adapt to changing conditions in the
circle dance of life.
Agriculture operates in a far less elegant manner. It’s a powerful, rowdy, perfectly unnatural,
manmade monstrosity. Its unpredictable
mood swings can range from feast to famine, prosperity to oblivion. In Mary Shelley’s classic horror story, the
foolishly clever Dr. Frankenstein got cold shivers when his ghoulish monster
turned to him and spoke these words, “You are my creator, but I am your master.”
Wild vegetation excels at recycling essential nutrients. On the other hand, field crops excel at
extracting and exporting nutrients, a slippery clumsy dance of destruction. For example, phosphorus is transferred from
the soil to the corn, from the corn to the hog, from the hog to the human, and
finally flushed down the toilet, bye-bye!
Little if any is returned to the field to replenish what was removed
from the soil.
Poop is precious.
Remember that. In 1588, Anzelm
Gostomski, a Polish gentleman, once proclaimed an eternal truth: “Manure is
worth more than a man with a doctorate.”
In the modern world, every shipment of food that moves from the local
countryside to faraway consumers is carrying away essential soil nutrients on a
one-way ride, never to return.
To keep a farm operation on life support for as long as
possible, efforts must be made to replace the deported nutrients. Over the centuries, farmers have kept soil
fertility on life support by applying stuff like sewage, manure, ashes, lime,
bone meal, seaweed, compost, peat moss, guano, synthetic fertilizer, and so
on. In China, human wastes have been
used as fertilizers for 5,000 years. Traditionally,
manure has been a popular fertilizer.
Gathering and spreading manure was far more fun than depleting the soil
and starving.
Even modest sized cities could religiously indulge in rituals
that recycled holy shit. In 1909, Franklin
Hiram King visited Kyoto, Japan.
While traveling down a road one lovely morning, he observed a long
caravan of men pulling cartloads of precious night soil from town. They were in the process of returning this
sacred life giving treasure to the fields where their food was grown.
Each cart carried six 10-gallon (38 l) covered containers of
delightfully fragrant plant food. King
noted that he passed 52 of these carts.
Then, on the return trip, he passed another 61 carts. Other caravans moved down other roads. He estimated that 90 tons of sewage was
hauled out of town on that morning. I
wonder if this was a daily routine.
With the growth of population and urbanization, returning more
and more human poop to fields that were farther and farther away, became
impractical. Eventually, imported
fertilizers were able to save the day (temporarily). Guano, phosphates, and synthetic ammonia were
powerful, but nonrenewable. Unfortunately,
they accelerated population growth, forcing the jumbo sized mob to zoom faster
down a one-way road to a less than utopian future.
Writing in 2001, when the population was a mere six billion,
Vaclav Smil estimated that 40 percent of the people alive in 2000 existed only
because of the intensive use of synthetic ammonia fertilizer. It had succeeded in shattering the population
ceiling (temporarily).
In order to survive in good health, all living plant and
animal organisms must acquire the mix of nutrients that are essential for them. Different species prefer different
mixes. David
Montgomery explained that there are three absolutely must-have macronutrients
for all plant and animal life (including you), for which there are no substitutes —
nitrogen (N), phosphorus (P), and potassium (K). General purpose “NPK” fertilizers contain portions
of all three. Humans acquire these
essential nutrients by eating plant and/or animal foods.
Nitrogen
(N)
Vaclav Smil noted that all living organisms require carbon,
hydrogen, oxygen, and nitrogen. In the
world, there are huge quantities of all four, but nitrogen is the oddball. The air we breathe is about 78 percent
nitrogen, but it’s not in a form that most living things can actually use.
In the air, it’s a gas that consists of tightly bonded pairs
of nitrogen atoms (N2) that are too stable to readily intermingle
with other atoms. Before it can be
utilized by living organisms, it must be transformed via a process called nitrogen fixation. In the soil are nitrogen-fixing bacteria that can combine
nitrogen and hydrogen to produce ammonia (NH3), a compound that can
nourish natural processes. Ammonia is 82
percent nitrogen.
These bacteria grow on the roots of leguminous plants,
like beans, soybeans, peas, chickpeas, peanuts, lentils, carob, alfalfa, and
clover. So, when you eat beans, your
body is able to absorb the usable nitrogen.
After a legume crop is harvested, the leftover plant material decomposes,
releasing fixed nitrogen into the soil, fertilizer for future crops. This “green manure” is plowed back into the
field.
When livestock graze, they absorb usable nitrogen from their
food, and then produce “brown manure” that generously boosts soil
fertility. You and I commonly get our
nitrogen when we digest the amino acids in high protein foods, including beans,
leafy greens, nuts, seeds, eggs, milk, and lean meat. At the rear end of the process, we expel a potent
brown fertilizer called poop.
Old fashioned low tech farming could produce modest harvests when
assisted by good luck and determined efforts.
Unlike modern industrial agriculture, old fashioned farm soil only provided
modest amounts of usable nitrogen. Low
nitrogen content results in low yields, while high content boosts them. So, nitrogen is a limiting nutrient, something like the
gas pedal in a car. So is phosphorus.
Ordinary soil generally contains modest amounts of N, P, and
K. Applying additional potassium (K) to
the soil does little or nothing to boost crop yields. But synthetic fertilizers can boost the
content of nitrogen and phosphorus beyond normal levels, and this actually promotes
bigger harvests. Of course, bigger
harvests can feed larger mobs of hungry humans.
In the short version of nitrogen history, there were two huge
leaps in fertilizer technology — guano and synthetic ammonia.
¶ Guano
is an organic fertilizer created by dense accumulations of bird shit or bat
shit. Seabirds often nest on islands,
where they are less vulnerable to pesky predators. For the same reason, bats prefer to shit in the
comfort and privacy of caves.
Each day, seabirds gobble up lots of yummy anchovies, return to
their nesting ground, and happily unload magic excrement. Century after century, more and more piles of
crap grew higher and higher. Mounds of guano
could have nitrogen content ranging from 8 to 21 percent by mass! Holy shit!
In arid regions, like the Pacific coast of South America, the
nesting islands were deeply covered with nutrient rich guano. Islands off the shore of Peru used to be
guano heaven — some deposits were over 200 feet (61 m) deep. In wetter regions, birds also colonize
offshore islands, and shit all over them, but rainy weather and humidity leaches
out vital nutrients.
According to Wikipedia,
“The rulers of the Inca Empire greatly valued guano, restricted access to it,
and punished any disturbance of the birds with death.” Guano was used for centuries by indigenous
folks.
By the 1840s or so, in Europe and North America, a persistent
brutally abusive relationship between farmers and their precious dirt was
taking a serious toll on soil fertility.
Meanwhile the mobs of hungry white folks continued snowballing. How in the <bleep> are we going to feed
them? Trouble ahead!
White folks first learned about magic guano in 1802, via the
writings of Alexander von Humboldt, which were translated into several
languages. Eventually, some ambitious lads
experienced a breathtaking revelation.
Holy shit! We could become filthy
rich guano tycoons!
As we all know, money is a devilish hallucinogen that can
turn kind and decent people into batshit crazy idiots. Consequently, humankind began a dramatic
transition from traditional food production that utilized local manure, into a
fast lane powered by imported bird shit.
In some locations, the guano had an exceptionally high content of
nitrogen, phosphate, and potassium. It
greatly excited the productivity of field crops.
And so, in the nineteenth century, guano was the world’s
super fertilizer, and a source of great wealth.
A guano gold rush was born. Nations
vigorously competed to claim ownership of guano islands. Disputes triggered the War of the Pacific
(1879-1884).
Traditions got tossed on the compost pile. Farmers no longer had to devote lots of time
to nutrient recycling. They didn’t need
to plant cover crops of nitrogen fixing legumes, or do crop rotations. They could simply buy what they needed, magic
bird shit, harvest far greater yields, and get rich quick.
Industrial scale guano mining was extremely disruptive to the
seabirds that squirted out the valuable shit.
On Peru’s guano islands, bird populations plummeted from the 53 million
in the late 1800s to just 4.2 million in 2011.
Of course, guano was a finite resource created over the
passage of countless millennia, and it was being extracted as fast as humanly
possible. Production peaked around
1870. Insatiable greed heads then
directed their attention to the saltpeter deposits in the deserts of
Chile. Saltpeter is sodium nitrate, a
compound that contained usable nitrogen.
J.
R. McNeill noted that by 1900, German farmers were highly dependent on
imported guano. Without it, they could
no longer feed the growing mob of hungry Germans. Gosh!
Wouldn’t it be wonderful if we could produce fixed nitrogen on an
industrial scale? Could it be
possible? Yes! Unfortunately, two Germans figured out how.
¶ Synthetic Ammonia.
I’d now like to introduce you to Fritz Haber and Carl Bosch. In 1909, chemist Fritz Haber invented a
process that could extract nitrogen from the air (N2), mix it with
natural gas (CH4), and embed it in ammonia (NH3), via an
energy-guzzling process of high heat and pressure. Synthetic
ammonia created a sharp turn in human history. (Years later, Haber invented Zyklon B, the
poison used in Nazi gas chambers.)
Carl Bosch figured out how to perform this catalytic process
on an industrial scale. Haber and Bosch
opened the first ammonia plant in Germany in 1911.
Ammonia was also a feedstock for explosives, which were in
high demand for countless bloody military adventures. So, many new ammonia plants were built. At the end of World War II, large quantities
of ammonia became available for other uses, and the production of synthetic
ammonia fertilizer soared.
In the second half of the twentieth century, the production
of synthetic NPK fertilizers skyrocketed: 4 million tons in 1940, 40 million
tons in 1965, and 150 million tons in 1990.
Far more food was produced, and the human population grew at an
explosive rate.
Today, the intended benefits of these fertilizers are maxing
out — applying more of it to a field no longer increases the size of the
harvest. But the potent fertilizer runoff
is able to continue increasing the contamination of groundwater, rivers, coastal
dead zones, and oceans.
Richard
Manning noted that when farmers apply synthetic fertilizer on a field, less
than half of it is absorbed by crop plants.
Fertilizer can acidify the soil. Some
of it dissolves and contaminates the groundwater that folks drink, and lots of
it runs off into waterways. Much of the
U.S. Corn Belt drains into the Mississippi River, which is an ecological
catastrophe.
Fertilizer runoff stimulates the growth of algal blooms. As the blooms die, they consume oxygen and
emit CO2. As the oxygen
content of the water is depleted (anoxia), this can cause everything to die
(eutrophication). The Mississippi flows
into the Gulf of Mexico, where it has created a dead zone the size of New
Jersey. The Baltic Sea is home to seven
of the of the world's ten largest marine dead zones. About half of U.S. lakes have low oxygen
content, and the number of dead zones in the world continues growing (415 in
2022).
The National
Science Foundation reported that fertilizer runoff is increasing the
nitrogen content in rivers and streams, where microbes convert it into nitrous
oxide (N2O), “a potent greenhouse gas, with a warming potential of
approximately 300 times that of carbon dioxide.” Nitrous oxide persists in the atmosphere a
long time, and promotes global warming and acid rain (it’s also a pain
reliever, laughing gas). Cow shit is
another source of nitrous oxide emissions, and their belches are a significant
source of methane.
In the twentieth century, global population skyrocketed at a
rate similar to the rapid increase in fertilizer use. Nitrogen and phosphorus are limiting nutrients,
and synthetic fertilizers exceled at sweeping away longstanding limits to crop
productivity. Julian
Cribb wrote that the wellbeing of most of humankind is now heavily reliant
on the use of these potent fertilizers to assure adequate food harvests.
Today, about 80 percent of synthetic ammonia is made using a
natural gas feedstock — a finite nonrenewable fossil energy resource. As natural gas prices rise, so will the cost
of nitrogen fertilizer, which will increase the cost of food. Political instability in the world is
increasing. A few nations have abundant
reserves of gas, while all nations are dependent on reliable access to
food. This presents many opportunities
for heavy handed dog-eat-dog mischief.
Phosphorus
(P)
Like nitrogen, phosphorus is also a limiting nutrient. It is always found in mixed compounds, never
in pure form. Much of the P in soil is
in a form that plants cannot use. This puts
a firm ceiling on crop productivity. In
NPK fertilizers, usable P is provided by phosphate (P2O5),
a mineral compound.
When phosphate is applied to a field, crop yields are
boosted. When it runs off cropland into
bodies of water, it can trigger eutrophication. Phosphorus enters your body at the mouth, and
departs via urine and excrement. It’s
possible to recover it from sewage and manure, but not cheap. When mixed 50/50 with water, your urine is an
excellent liquid fertilizer that contains both nitrogen and phosphorus — and
it’s free. Waste not!
Fred
Pearce noted that every living cell needs P, and there is no
substitute. It’s as essential to plant
life as water is. We are great at
misusing it, suck at recycling it, and it’s vital for feeding humans and other
critters. Each year, the world mines 170
million tons of phosphate.
The world’s primary source of phosphate rock is an open-cast
mine in the Western Sahara, a region currently controlled by Morocco — an
unpleasant situation that irritates the native Saharans. Political instability in the region could
disrupt the production and distribution of phosphate, and generate a food
crisis in many nations.
So, demand is rising, most of the world’s best phosphate
reserves are gone, and those that remain are in just a handful of countries. Most of these reserves are in hard rock form,
which requires vastly more fossil energy to mine and process. There are also large deposits of phosphates
in deep sea locations, but mining them would be deeply expensive.
When will phosphate production peak? That’s a highly contentious question, because
accurately estimating the remaining reserves requires lots of guesswork. Today, of the three essential NPK nutrients,
P is the most worrisome to experts.
Just as I was about to send this info to the world, my faithful
muse gave me a dope slap and directed me to an important research paper. It’s written in super-cryptic science jargon,
and ordinary readers (like me) may suffer some permanent brain damage, but it’s
a fascinating horror story.
Christine
Alewell and team put a spotlight on the latest news. If global heating doesn’t blindside
industrial civilization, phosphorus depletion will. Big Mama Nature brilliantly guided the
evolution of wild ecosystems that did a wonderful job of protecting precious
topsoil and perpetually recycling essential nutrients. Sadly, cleverness has pulled the rug out from
under this delicate balancing act. The tilling
of agricultural soils eliminates the protective covering of wild vegetation, and
exposes the delicate treasure below.
When P is not locked within solid rock, its water
soluble. When rain splatters directly on
pulverized farm soil, gravity carries the P runoff elsewhere, like wetlands and
streams. Erosion causes about half of
the P depletion in farm soil. As P
content decreases, so does the productivity of the field. Harvests shrink.
Alewell noted, “The world’s soils are currently being
depleted in P in spite of high chemical fertilizer input.” In poor countries, where folks can’t afford
potent fertilizer, the rate of P depletion is even higher. In the long run, agriculture is not
sustainable. “Soil phosphorus (P) loss
from agricultural systems will limit food and feed production in the future.”
To continue producing chemical fertilizer requires continued mining
of nonrenewable geological deposits of P, an increasingly limited resource. The P moves in a one-way flow from the mines,
to the agricultural land, into freshwaters, and finally into oceans.
The “organic management” of P is also unsustainable. A cornfield extracts P from the soil. Then, the harvested grain is sent somewhere
else, along with its P content. Added
manure and compost won’t replace all of the P exported. Similarly, livestock grazing extracts the P
from the greenery consumed. Some of it
is returned to the land via manure and urine, but some of it is sent away to
the meat processor, never to return.
Potassium
(K)
In plants, potassium is important for the synthesis of
protein. The potassium component of NPK fertilizer
is provided by a variety of minerals rich in potash (K2O) that are
found in the salt beds of ancient seas and lakes. The K added to NPK fertilizer comes from
nonrenewable mined sources. David
Montgomery noted that “potassium occurs in rocks almost everywhere in forms
readily used as natural fertilizer.” We
don’t have to worry about near term potassium shortages. Lots of other future crises are closer to the
front of the line.
Toxic
Sludge
Abby
Rockefeller wrote a fascinating essay that thoroughly explored the long and
exciting history of human pooping and peeing.
In modern cities, sewage treatment plants regularly generate sludge,
which has to be removed and put somewhere.
Somewhere is often cropland.
Besides the holy shit that happily splashes in your toilet, sludge also contains lots of weird stuff produced by industrial civilization. For example, volatiles, organic solids, disease-causing pathogenic organisms, heavy metals, and toxic organic chemicals from industrial wastes, household chemicals, and pesticides. Crops grown in fields treated with toxic sludge produce foods that may be less than wholesome.
BOTTOM LINE: Bill
McGuire reported that intensive industrial agriculture is depleting the quality
of cropland soils. In many parts of the
world, including in the U.K., E.U., and the U.S., these soils are becoming “effectively
sterile in the absence of regular fixes of artificial fertilizer.” No free lunch. No sustainable agriculture. But eight billion get to pee and poop every
day (for a while). Hooray!
