The skin of the Earth, the treasure trove of life, the foundation of labor, and the final destination of life.
Ecological and sociological exploration of soil
A soil ecology expedition completed by digging and running around the ground.
A grand story that changed the fate of humanity lies in a handful of dirt!

A story about the soil around the world and the people who depend on it, told by an ecologist who feels and records the breath of the soil.
Examining the relationship between land and people in various cultures around the world, it addresses contemporary human agricultural culture, soil biology and chemistry, terrestrial landscape changes, climate change, and sustainability issues.
From the landscape of Jindo, Korea, where graves and fields coexist, to the wisdom of Himalayan slash-and-burn farmers, to the fierce activity of earthworms that have 'invaded' the polar regions, from the dramatic moment when soil was born on a Hawaiian volcanic island to soil erosion sites around the world, amazing stories from the soils of the Earth, diligently collected through footwork, unfold.

In 16th-century China, associations or guilds were organized to collect urban dung.
(...) In Edo and Osaka during the Tokugawa period, if the landlord owned the excrement from the building, the tenant had the right to sell urine.
The building owner set the rent based on the income he would make from selling the tenants' excrement, and sold the collected excrement to excrement collectors who came by at the right time.
A dung collector was a trader who bought dung in the city and sold it in the countryside.
As a resource, feces fit well with the capitalist circulation of money.
The excrement of people moving from city to country was not only a food solution in Asia, but also a way to maintain public sanitation in rapidly growing cities.
--- p.37~38

Nitrogen is a precious element in terrestrial ecosystems.
Ninety percent of temperate ecosystems and nearly half of tropical ecosystems are nitrogen-limited.
This means that plant production increases simply by adding nitrogen to the soil.
A characteristic of a nitrogen-limited ecosystem is that even if other nutrients such as phosphorus or potassium are added, there is no significant increase in production, but when nitrogen is added without any other nutrients, there is an abrupt response.
--- p.46

Composting is simply the process of adjusting the ratio of carbon to nitrogen.
The desirable carbon to nitrogen ratio for composting raw materials is often considered to be around 30 to 1.
If the carbon content is lower than 30 units, it will be in a nitrogen-excess state and will produce foul-smelling ammonia, and if it is higher than 30, it will rot very slowly like the straw mentioned above.
The carbon to nitrogen ratio of the finished compost, which makes it an optimal fertilizer when applied to the soil, is 10 to 15 to 1.
This is where shit's strongest point lies.
--- p.49

Nitrogen makes up 78 percent of atmospheric molecules.
In terms of quantity, there are 4,000 trillion (3.9×10^15) tons of nitrogen floating in the Earth's atmosphere, so our bodies, which walk with only the soles of our feet on the ground, are like wading through a sea of ​​nitrogen.
--- p.51

It is not possible for lettuce and peppers to grow thick and green in a wasteland of yellow soil devoid of any organic matter.
Korea is one of the countries that provides the largest amount of nitrogen fertilizer.
In 2021, 137 kilograms of nitrogen fertilizer per hectare were applied.
--- p.59

Even in the mountainous regions of Nagaland, where weathering and erosion occur relentlessly, soil remains because roots create the soil.
Just as there are roots because there is soil, there are also soil because there are roots.
Without the tenacity of their roots, tropical trees would not be able to reach their full growth potential despite the warm, water-rich environment.
--- p.83

In 2014, I met Professor Kim Pil-ju of Pyongyang University of Science and Technology in Seoul.
I asked him, an agronomist who has dedicated his life to solving North Korea's food problem, what machine would be needed to increase North Korea's agricultural production?
“It’s a rock crusher.” It was an unexpected answer.
“North Korea’s soil acidification is so severe that lime must be spread, so a limestone crusher is needed.” --- p.87

Earth is the beginning and the end of humanity.
As University of Wisconsin soil scientist Francis Hall (1913–2002) said, “For a moment we are not soil.”
Genesis says that even for a 'moment' the earth is the foundation of labor.
Destroying the soil is killing one's homeland and destroying a place to return to, yet it is the fate of humans to have to till the soil in order to make a living.
The plow is at the center of the irony that the labor we do to earn a living betrays humanity.
--- p.107

The Green Revolution saved countless people from starvation, but it also created problems of population growth and environmental destruction.
In this vein, conservation agriculture is a paradigm shift in farming practices that protects soil cover and promotes biodiversity.
However, the plow problem was only replaced by a herbicide problem.
Organic farming, an alternative, rejects the chemical fertilizers and pesticides created by modern agricultural technology and continues the long tradition of increasing agricultural productivity through an understanding of the ecological system, but it still faces the problem of the plow.
Innovation is still desperately needed in the place of the plow.
--- p.133

Rice has a unique physiology that allows it to transform into a wetland plant depending on the situation.
In other words, depending on whether it is submerged in water or not, ventilation tissue may or may not be formed.
The only major crop that can grow and root in waterlogged soil is rice.
When competing plants—commonly called weeds—choke in the water-filled fields, rice plants put on snorkels.
Therefore, filling the field with water to submerge the soil is a strategy to irrigate the rice while also removing weeds.
--- p.147

Compared to field soil, paddy soil has a higher organic matter content even when the same amount of dead organisms are buried there.
While artificial wetlands built by farmers increase soil organic matter content by slowing the rate of organic matter decomposition, ploughing and tilling further increase the organic matter content by forcing the remains of weeds and other organisms living in the paddy water into the anaerobic soil.
--- p.156

In other words, filling the fields with water is also a device to prevent soil acidification, which is a consequence of crop cultivation.
So, what would be the rational choice for an East Asian or Korean farmer, given the choice between rice paddies and dry fields? Whether it's disaster resistance or the sustainability it leaves for future generations, if possible, they'd likely choose rice paddies.
Despite high population densities and concentrations, rice farming in Asia has been able to persist for thousands of years without depleting soil fertility because rice was grown in flooded paddies rather than dry fields, and because the physiological characteristics of the rice plant and the integration of rice paddies into an organic system.
--- p.159

In 2008, when I was tired of being an assistant professor and was walking along the river, a groundbreaking paper was published about my walks.
Bob Walter and Dorothy Meritz made the radical claim that the banks blocking the rivers on both sides of the falls were not natural but the product of a mill dam.
It was said that the rivers of Piedmont are shaped the way they are today because of European settlers.
--- p.225~226

If earthworms arrived with the white man, what would the Ojibwe call them? Ojibwe speakers, who lived around the glaciated Great Lakes, likely never encountered earthworms, so perhaps they didn't even have a word for them. Does the Ojibwe language reflect the arrival of earthworms with the white man? I reached out to Professor John Nichols, an Ojibwe language researcher at the University of Minnesota's Department of American Indian Studies.
“Oh! I see.
The earthworm was an invasive species.
Now it all makes sense.
“I’ve always wondered why there’s no word for earthworm in Ojibwe,” he said. “For example, an Ojibwe speaker I interviewed at the Canadian border used the long phrase “long, coiled worm” (Ojibwe transliterated into English as moose gaa-ginwaabiigizid) to refer to earthworms.
--- p.279~280

On the other side of those who sing the praises of earthworms, I have been studying earthworms.
When it is said that earthworms make holes in the field to loosen the soil and allow water and air to flow, I have seen the opposite phenomenon.
With the invasion of earthworms, the soils of forests in Minnesota, Alaska, and Sweden have changed from fluffy, water- and air-permeable structures to hard, compact structures of mineral matter.
When it comes to earthworms, they help plants grow by circulating organic matter and nutrients, and I have personally witnessed and documented how, in a forest in an old glacial zone, hundreds of years of accumulated nutrients were lost in a matter of years due to an invasion of earthworms.
When I say that earthworms create fertile soil, I see native plants and animals losing their habitats to invasive earthworms.
When I hear the argument that we should actively utilize earthworms to revitalize the soil and reduce waste, I hope that the earthworms will just do their job well where they are now.
--- p.283

5 million years old! You won't find dirt older than this in Hawaii.
If you try hard, you might find it? That's not what I mean.
The islands beyond Kauai cannot exist above ground, having succumbed to subsidence and erosion over more than five million years and soon submerged.
If we imagine the earth as an actor that shows the dynamics of life and death, then the island is the stage.
Just as actors appear and disappear, so too does the stage.
--- p.302

The sight of new soil and new land being created on the Big Island is dramatic.
A hole in the earth's crust must be torn, red lava must flow, burning volcanic ash must fly, forests must catch fire, animals and people must flee, and the sky must turn ashen before a new land surface can be created.
It seems that the soil that has endured the arduous process of birth cannot have a weak body.
But the earthy body, contrary to our expectations that it would be unchanging and stable, barely exists.
On a volcanic island, soil is the product of lava formed from magma falling into the thermodynamic hell of the landmass.
Organic matter in the soil is also in an unstable state, temporarily bound to solar energy by atmospheric carbon dioxide and underground water.
The earthen body is still constantly decomposing towards a state of thermodynamic equilibrium under various winds.
--- p.317

Soil respiration is a great breath.
The amount of carbon dioxide emitted from burning fossil fuels, the main culprit of climate change, is 36.8 billion tons as of 2023.
The amount of carbon dioxide that the soil releases each year is roughly ten times that amount.
Yet, until humans began burning fossil fuels, atmospheric carbon dioxide concentrations did not exceed 300 ppm for the past 800,000 years.
Because on a global scale, soil has not yet reached the edge of carbon neutrality.
Saying that soil is carbon neutral means that the amount of carbon dioxide that the soil exhales has been converted into carbon dioxide from the organic matter produced through photosynthesis, which has entered the soil through the dead bodies of plants and animals.
The reason why the concentration of carbon dioxide in the atmosphere has been stable throughout Earth's long history is because terrestrial ecosystems, including soil and plants, have never strayed from the edge of carbon neutrality, and the oceans that surround 70 percent of the Earth have never strayed from the edge of carbon neutrality.
--- p.338~340

Atmospheric carbon dioxide concentrations vary with seasons.
The three reasons for this are the concentration of land in the Northern Hemisphere, plant photosynthesis, and soil respiration.
(...) The difference in carbon dioxide concentration between summer and winter is 5 to 7 ppm at the Mauna Loa Observatory in Hawaii.
It is truly a shame that the breath of this beautiful and wonderful Earth is overshadowed by the disastrous news of the annual average carbon dioxide concentration increasing year after year.
--- p.344

The Ajangmok tree seen from Sangmanri Village revealed its existence on its own without any effort to find it.
This elegant pine tree was at least a foot taller than the surrounding, evenly growing trees.
Within a 20-30 meter radius around the ajang tree, the surrounding smaller trees, which were all the same height, seemed to be oppressed by the ajang tree's might.

--- p.375