The dirt beneath your feet is only the top layer — maybe only one or two feet thick. Maybe not even that much. It is made mostly of small particles of rock, some clay, and dead plant material. And if it is healthy soil, it also contains an astounding amount of life. One handful of healthy soil contains more living organisms than there are people on earth. These living things include worms, bacteria, very small insects, and fungi.
Underneath the topsoil is subsoil, also about a foot or two deep. It has less life in it, and some plant roots don't penetrate into it. Beneath that is bedrock.
It takes a long time for topsoil to build up into something that plants thrive on. Erosion naturally and inevitably removes topsoil by wind when it's dry and by washing some away some topsoil when it rains. If the topsoil is building up — by falling leaves decomposing and feeding the microorganisms, and by the action of plant roots feeding fungi, which feeds other soil organisms, and by earthworms and other creatures — if the topsoil is building up at the same rate as soil is eroding, then everything is fine. But if soil is eroding faster than it's being built, eventually plants won't grow very well on it.
Have you seen what the Middle East looks like? When you see the vast areas of bare ground, you're seeing what happens when erosion happened faster than topsoil accumulation. Eventually nothing can grow in it. The topsoil is gone and the subsoil is gone. This is not unique to the Middle East, but that's where agriculture originated, so they got a "head start."
The same thing is happening everywhere. "Around the globe," says Judith Schwartz, "we're losing topsoil somewhere between ten times (in the United States) and forty times (China and India) faster than we're generating it..."
When a field is plowed (and before crops have taken root) it is vulnerable to erosion. If it dries out and the wind starts blowing, some of that topsoil blows away. If it rains, some of that topsoil washes away. When it rains and you see a river that looks muddy, you are usually looking at topsoil on its way to the ocean.
When grasslands are grazed unnaturally, bare ground starts to show. That bare ground can also blow away in the wind or wash away in the rain. Much of the living organisms in the soil die off, releasing their carbon back into the air.
All of us have a stake in the health of soil. Topsoil is a thin barrier between survival and starvation. History is a broken record playing the same thing over and over again: Agriculture in fresh land is productive, and the human population grows. Farming practices expose and exhaust the soil, causing diminishing agricultural returns, which eventually causes people to move somewhere else and do it all over again. Read the book, Dirt: The Erosion of Civilization for the history of the world as seen through the ultimate driving force behind most historical events — soil erosion.
And here we are in the present, still doing the same thing. The population is growing and we're losing topsoil. But we are all out of new places to move.
One long-term solution to this is to reduce the human population. Luckily, the best way to achieve that is something that ought to be done anyway: Make sure women everywhere have human rights.
But in the meantime, we need to restore our precious topsoil. Holistic Planned Grazing does exactly that. Here's how it works.
Adam Khan is the author of Self-Reliance, Translated and Principles For Personal Growth. Follow his podcast, The Adam Bomb.