14 Dirty Photos That Show Why Soil Matters

A new United Nations report published on World Soil Day digs into how humans mistreat Earth’s soils.

Let’s face it: we treat soil like dirt. And for all our sakes, we shouldn’t.

That’s the sweeping conclusion of the Status of the World's Soil Resources Report, the United Nations’ first worldwide assessment of the Earth’s soils. The sobering analysis—announced on Friday, 2015’s World Soil Day—underscores the difficulties facing the overlooked loamy mat that dusts our planet’s landforms.

“It’s like the air or water, giving a whole range of ecosystem services to all of us,” says Luca Montanarella of the European Union’s Institute for Environment and Sustainability, who served as the report’s lead author. “When people look out the window,” however, “they see the landscape—they don’t look below ground.”

Scientists also struggle with fully appreciating soil, given that it is “arguably the most complex substrate on Earth,” says soil ecologist Bala Chaudhary of Loyola University Chicago.

“You’ve got strong gradients—of pH, of temperature, of moisture—and millions of organisms, some of [which] are fighting and some [of which] are helping each other,” she says. “And that’s all happening in the scale of one centimeter.”

“Imagine that scaling up to a field or a landscape,” Chaudhary adds. “That complexity is almost hard to comprehend.”

In the face of such challenges, researchers are hungry for answers—because in the future, they don’t want to suffer from literal hunger. A changing climate and growing human population will continue to place enormous pressures on the world’s arable lands, which will need to produce 70 percent more food by 2050.

Current human practices, however, aren’t exactly helping. Excessive cultivation has sapped many soils of vital nutrients. Sprawling urban areas have eaten away at farmable lands, sickening them from chemical runoff or choking them under impermeable, man-made coverings. And a football field’s worth of farmable soil is lost every five seconds to erosion, soils’ gravest global threat.

But saving soils will not only secure humankind’s food supply, but it will prove key in combating climate change. Soils hold onto more carbon than all the vegetables, animals, and minerals sitting atop them, making them an enormous “climate sink.” In fact, increasing soils’ carbon content by 0.4 percent annually through conservation and better management could stabilize humankind’s dangerous carbon emissions—and improve crop yields, too.

In other words, “if soil is managed poorly, it is impossible to imagine an optimistic future,” the UN report’s technical summary concludes. But if we can conserve and take care of soil as something “to be preserved for future generations,” as Montanarella urges, we can literally break new ground.

In the spirit of World Soil Day, we’ve assembled a gallery that showcases Earth’s beautifully diverse soils and how humans interact with them, drawing significantly from Jim Richardson’s work for National Geographic’s September 2008 cover story.

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